Endocrine Pathology (Thyroid, Adrenal, Pituitary) MCQs

Pathology · 121 free questions with answers & explanations.

1. A 45-year-old woman has a thyroid mass. Biopsy shows follicular patterned cells with capsular invasion but NO vascular invasion on extensive sampling. IHC shows loss of PTEN and RAS mutation. This is classified as:
2. Medullary thyroid carcinoma (MTC) arises from parafollicular C cells and secretes calcitonin. In familial MTC (MEN-2), the precursor lesion is:
3. A 35-year-old woman has a 2 cm thyroid nodule. Fine needle aspiration cytology shows Bethesda category V (suspicious for malignancy) with nuclear clearing, grooves, and intranuclear pseudoinclusions. Molecular analysis reveals a BRAF V600E mutation. The final thyroidectomy specimen shows a 2.1 cm tumor with complete fibrous capsule, focal capsular penetration but NO vascular invasion. How should this be classified?
4. A 45-year-old man with MEN2A syndrome undergoes prophylactic thyroidectomy. Histology reveals medullary thyroid carcinoma (MTC). Immunohistochemistry would be POSITIVE for which combination of markers, confirming the diagnosis?
5. A 38-year-old woman presents with hypertension, hypokalemia, and a 2.5 cm right adrenal adenoma on CT with lipid-rich appearance (HU < 10 on unenhanced CT). Biochemistry confirms primary aldosteronism. Adrenal vein sampling (AVS) shows a lateralization ratio of 4:1. Pathologically, which somatic mutation is most commonly found in aldosterone-producing adenomas (APAs)?
6. Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. The most frequent molecular alteration in sporadic PTC is:
7. A 38-year-old woman presents with hypertension, hypokalemia, metabolic alkalosis, and suppressed plasma renin. Adrenal CT shows a 1.5 cm left adrenal adenoma. Adrenal vein sampling shows lateralization to the left. The biochemical mechanism of hypertension in this condition is:
8. A 40-year-old woman has a thyroid nodule. FNA shows papillary thyroid carcinoma (PTC). The molecular alteration most frequently found in conventional PTC and which drives MAPK pathway activation is:
9. A patient with MEN2A has a pheochromocytoma and medullary thyroid carcinoma. The RET proto-oncogene mutation in MEN2A most commonly affects which codon, and what is the functional consequence?
10. A 35-year-old woman with Cushing disease has a pituitary microadenoma secreting ACTH. Histologically, the adenoma cells show characteristic 'Crooke hyaline change' in surrounding non-adenomatous corticotrophs. This change represents:
11. On thyroid biopsy, a tumor shows cells with ground-glass ('Orphan Annie eye') nuclei, nuclear grooves, pseudoinclusions, and psammoma bodies. The characteristic molecular alteration in this tumor type and its associated hereditary syndrome are:
12. A 40-year-old man with hypertension and hypokalemia is found to have a 2 cm right adrenal adenoma on CT and an elevated aldosterone-to-renin ratio. Which immunohistochemical marker is most useful to distinguish an aldosterone-producing adenoma from cortisol-producing adenoma?
13. Pheochromocytoma is characterized by the 'rule of 10s' classically. Modern genetic data has revised the hereditary rate. According to current evidence, what proportion of pheochromocytomas/paragangliomas are associated with germline mutations?
14. A 40-year-old woman undergoes total thyroidectomy for a 3 cm thyroid nodule. Histology shows well-formed follicles lined by cells with ground-glass ('Orphan Annie eye') nuclei, nuclear grooves, and intranuclear pseudoinclusions — but the entire tumor is encapsulated with NO capsular or vascular invasion. According to the current WHO classification (2022), this tumor is classified as:
15. A 35-year-old woman presents with hypertension, hypokalemia, and suppressed plasma renin activity. CT abdomen shows a 1.8 cm right adrenal adenoma. Adrenal vein sampling confirms right-sided aldosterone excess. The pathological basis of autonomous aldosterone secretion in this adenoma involves mutation in which ion channel/ATPase?
16. A pheochromocytoma patient undergoes adrenalectomy. Histology shows large chromaffin cells with granular cytoplasm, arranged in 'Zellballen' (ball-like nests). However, there is NO reliable histological feature that can distinguish benign from malignant pheochromocytoma. The diagnosis of malignancy in pheochromocytoma requires:
17. A 35-year-old woman has a thyroid nodule with FNA showing cells arranged in papillary clusters with nuclear grooves, intranuclear pseudoinclusions, and pale ('Orphan Annie eye') nuclei. Molecular testing shows BRAF V600E mutation. The WHO 5th edition classification designates this as:
18. A 45-year-old man with MEN2A syndrome undergoes prophylactic thyroidectomy. In addition to medullary thyroid carcinoma (MTC), which other endocrine tumor characterizes MEN2A?
19. A 32-year-old man has episodic hypertension, palpitations, and diaphoresis. 24-hour urine metanephrines are markedly elevated. Imaging reveals an adrenal mass. Histology cannot reliably distinguish benign from malignant pheochromocytoma. Which scoring system is used for risk stratification?
20. A 42-year-old woman has a 1.8 cm thyroid nodule. Fine-needle aspiration is classified as Bethesda VI (malignant). Histology post-thyroidectomy shows follicular architecture with ground-glass ('Orphan Annie eye') nuclei, nuclear grooves, and nuclear pseudoinclusions, without vascular or capsular invasion. Molecular testing of this tumor would most likely reveal:
21. A 48-year-old with hypertension and hypokalemia is found to have an adrenal adenoma on CT. Adrenal vein sampling confirms primary aldosteronism lateralizing to the left adrenal. Aldosterone-producing adenoma (Conn's tumor) most frequently harbors a somatic mutation in which gene?
22. A 30-year-old woman has pituitary adenoma causing Cushing disease. After transsphenoidal resection, she goes into remission. Five years later, cortisol rises again. Pituitary MRI shows a new lesion in the same region. Molecular analysis of the recurrent tumor reveals loss of the USP8 mutation present in the original tumor and emergence of a new BRAF V600E mutation. This scenario best illustrates:
23. Papillary thyroid carcinoma (PTC) arising in patients exposed to ionizing radiation in childhood (e.g., post-Chernobyl) predominantly carries which molecular alteration?
24. Adrenocortical carcinoma (ACC) staging uses the ENSAT classification. The immunohistochemical marker that most reliably distinguishes ACC from adrenocortical adenoma is:
25. A pituitary adenoma resected from a 45-year-old with acromegaly shows Ki-67 of 4% and p53 positivity. Per the WHO 2022 pituitary neuroendocrine tumor (PitNET) classification, this tumor is designated as:
26. A 42-year-old woman undergoes thyroidectomy for a 3 cm thyroid mass. Histology shows follicular-patterned cells with nuclear features including nuclear enlargement, oval nuclei, nuclear membrane irregularities ('nuclear grooves'), nuclear clearing ('Orphan Annie eyes'), and nuclear pseudo-inclusions. There is no capsular or vascular invasion. Molecular testing shows BRAF V600E mutation. What is the correct WHO (2022) diagnosis, and how does BRAF V600E alter clinical management compared to RAS-mutated follicular-patterned thyroid tumors?
27. A 35-year-old man presents with episodic hypertension, diaphoresis, headache, and palpitations. 24-hour urinary metanephrines and normetanephrines are markedly elevated. CT abdomen shows a 4 cm right adrenal mass. He has a family history of renal cell carcinoma and cerebellar hemangioblastoma. Which syndromic cause is most likely, and which molecular pathway is constitutively activated in these tumors?
28. A 28-year-old woman with Cushing's syndrome has suppressed ACTH on plasma assay, elevated 24h urinary cortisol, failure to suppress on high-dose dexamethasone, and unilateral adrenal mass on CT. Adrenalectomy specimen shows a 5 cm cortical tumor with 6 mitoses per 50 HPF, necrosis, and venous invasion. Using the Weiss scoring system, what is the threshold for malignancy and what is the most important molecular alteration distinguishing adrenocortical carcinoma from benign adrenocortical adenoma?
29. The 2022 WHO Classification of Thyroid Tumors introduced the category of 'non-invasive follicular thyroid neoplasm with papillary-like nuclear features' (NIFTP). NIFTP was separated from invasive encapsulated follicular variant of papillary thyroid carcinoma (PTC). The DEFINING criterion for classifying a lesion as NIFTP rather than encapsulated follicular variant PTC is:
30. Primary hyperaldosteronism (Conn syndrome) is the most common cause of secondary hypertension. Adrenal vein sampling (AVS) is the gold standard for lateralisation. Histopathologically, bilateral adrenocortical hyperplasia in primary hyperaldosteronism most commonly results from what molecular mechanism identified in recent molecular studies?
31. A 45-year-old man with MEN2A syndrome has prophylactic thyroidectomy. Histology shows C-cell hyperplasia progressing to medullary thyroid carcinoma (MTC). The RET proto-oncogene mutation responsible for MEN2A most commonly involves which codon, and which receptor signalling pathway is constitutively activated?
32. A 40-year-old woman undergoes thyroidectomy for a 2.5 cm follicular thyroid lesion. Histology shows an encapsulated follicular-patterned tumour with definitive capsular invasion (a few foci of tumour cells penetrating through the full capsule thickness) but no vascular invasion. According to the WHO 2022 endocrine tumour classification, what is the diagnosis?
33. A patient with adrenal cortical carcinoma (ACC) has a mass showing 9 mitoses per 10 HPF, atypical mitoses, venous invasion, fibrous bands, and necrosis. Using the Weiss scoring system, what score does this tumour receive and what does it mean?
34. A 30-year-old man presents with secondary hypertension. 24-hour urine catecholamines are markedly elevated. CT shows a 4 cm right adrenal mass. Germline testing reveals a SDHB mutation. Which is the most important clinical implication of SDHB mutation in this context compared with a sporadic pheochromocytoma?
35. A 40-year-old woman with a 2 cm thyroid nodule undergoes FNA cytology showing nuclear grooves, nuclear inclusions (pseudo-inclusions), overlapping nuclei, and powdery chromatin with pale nuclear clearing. Molecular testing reveals a BRAF V600E mutation. According to the WHO 2022 classification of thyroid tumors, what is the most appropriate histological diagnosis after surgical resection, and why does BRAF V600E alone not establish the diagnosis of malignancy on FNA?
36. In the WHO 2022 classification, all adrenocortical carcinomas (ACC) are now graded using the Helsinki score. A 50-year-old patient has a 12 cm adrenal mass. On resection: 32 mitoses/50 HPF, diffuse architecture, vascular invasion, and Ki67 of 30%. According to the Weiss criteria (still applied alongside Helsinki score), which constellation meets criteria for malignancy?
37. Multiple endocrine neoplasia type 1 (MEN1) is caused by germline mutations in the MEN1 gene encoding menin. Menin functions as a tumor suppressor. Which molecular function of menin explains why its loss promotes tumorigenesis in endocrine cells?
38. The WHO 2022 classification of thyroid tumors introduced the category of low-risk neoplasms including NIFTP. A thyroid nodule fulfills criteria for NIFTP (Noninvasive Follicular Thyroid Neoplasm with Papillary-like nuclear features) if it has:
39. Phaeochromocytoma and paraganglioma (PPGL) are now recognized to be hereditary in approximately 40% of cases. The germline mutation most commonly associated with malignant PPGL (paraganglioma with metastasis), particularly of the head and neck paraganglioma subtype, involves:
40. A 55-year-old woman undergoes thyroidectomy for a thyroid nodule. Histology shows papillary architecture with nuclear features: ground-glass (Orphan Annie eye) nuclei, nuclear grooves, pseudoinclusions, and overlapping nuclei. There is no capsular or vascular invasion. The tumor measures 0.8 cm. According to WHO 2022 endocrine classification, this is best classified as:
41. A 40-year-old patient with hypertension, hypokalemia, and suppressed renin has an adrenal adenoma on CT. Adrenal vein sampling shows a lateralization ratio of >4:1 favoring the left side. Histology of the surgically removed adenoma shows lipid-rich clear cells with mild nuclear atypia. The Weiss criteria for adrenocortical carcinoma requires at least 3 of 9 features. Which feature, if present alone, is most predictive of malignancy?
42. A 30-year-old woman has hyperprolactinemia, secondary amenorrhea, and MRI shows a 1.5 cm pituitary mass (macroadenoma). Surgical pathology: immunostaining for prolactin is positive but the Ki-67 labeling index is 12% and p53 is strongly positive. The 2022 WHO classification of pituitary tumors introduced a new term for pituitary adenomas to replace the traditional term. These tumors are now called:
43. A 45-year-old woman with longstanding Hashimoto thyroiditis develops a thyroid lymphoma. Biopsy shows diffuse infiltration by medium-to-large B cells with a prominent lymphoepithelial lesion pattern, destroying thyroid follicles. Which lymphoma type is most common in this setting, and what is the typical immunophenotype?
44. Adrenocortical carcinoma (ACC) is a rare but aggressive malignancy. The Weiss criteria for malignancy include 9 histological parameters. Which molecular alteration, found in ~90% of pediatric and ~50% of adult ACCs, most strongly supports TP53 germline testing?
45. A 38-year-old woman presents with secondary amenorrhea and galactorrhea. MRI shows a 15 mm pituitary adenoma. Immunohistochemistry of the surgically resected tumor shows strong positivity for prolactin and Pit-1 transcription factor. Per WHO 2022 pituitary adenoma classification, this tumor is reclassified as which entity, and which variant is considered 'high-risk'?
46. A 30-year-old woman with a thyroid nodule undergoes FNA. The cytology report reads 'follicular neoplasm; cannot exclude follicular carcinoma' (Bethesda Category IV). The definitive distinguishing feature between follicular adenoma and follicular carcinoma on histopathology is:
47. Pheochromocytoma is associated with RET proto-oncogene mutations in MEN2A and MEN2B. The SDH (succinate dehydrogenase) subunit mutation most associated with metastatic (malignant) pheochromocytoma is:
48. A 35-year-old woman undergoes thyroid biopsy for a solitary nodule. Histology shows follicular cells arranged in follicles without papillary architecture. Nuclear features are absent. Vascular and/or capsular invasion is demonstrated. What is the diagnosis and the clinical significance of vascular invasion pattern?
49. A 45-year-old woman is investigated for hypertension, hypokalemia, and low plasma renin activity. CT abdomen shows a 1.8 cm right adrenal adenoma. Adrenal vein sampling confirms autonomous aldosterone hypersecretion from the right adrenal. What is the pathological mechanism of hypertension in Conn's syndrome?
50. A patient develops Waterhouse-Friderichsen syndrome. Bilateral adrenal hemorrhagic necrosis is present at autopsy. The mechanism of adrenal destruction in this condition is BEST explained by:
51. A 45-year-old woman undergoes thyroidectomy for a thyroid nodule. Histology shows follicles filled with colloid, nuclear features of ground-glass 'Orphan Annie eye' nuclei, nuclear grooves, intranuclear pseudoinclusions, and psammoma bodies. The diagnosis is papillary thyroid carcinoma (PTC). Psammoma bodies in PTC represent what pathological process?
52. A 35-year-old woman presents with hypertension, hypokalaemia, metabolic alkalosis, low renin, and elevated aldosterone. CT abdomen shows a 2 cm adrenal cortical adenoma. The zona of the adrenal cortex that is hyperplastic/neoplastic in primary hyperaldosteronism (Conn syndrome) is:
53. A 25-year-old woman has a prolactin level of 180 ng/mL, galactorrhoea, and amenorrhoea. MRI shows a 12 mm pituitary tumour with suprasellar extension. Which immunohistochemical marker is MOST expected on biopsy of this tumour?
54. Medullary thyroid carcinoma (MTC) arises from parafollicular C cells and secretes calcitonin. In familial MTC associated with MEN2, the RET codon 634 point mutation confers the HIGHEST risk phenotype. Prophylactic thyroidectomy is recommended at what age in MEN2A patients with codon 634 mutation (ATA risk category C)?
55. A 40-year-old woman has a thyroid nodule. FNA shows nuclear clearing ('Orphan Annie eye' nuclei), nuclear grooves, and nuclear pseudoinclusions. The MOST likely diagnosis is:
56. Waterhouse-Friderichsen syndrome is acute bilateral adrenal hemorrhage most commonly caused by which organism?
57. A pheochromocytoma that is malignant is defined by which criterion?
58. A 35-year-old woman has a thyroid nodule. FNA cytology shows cells arranged in a papillary configuration with characteristic nuclear features: nuclear grooves, intranuclear pseudoinclusions (Orphan Annie eye nuclei), and powdery chromatin. Molecular analysis would most likely reveal:
59. A 10-year-old child presents with a calcified suprasellar mass causing bitemporal hemianopia and growth retardation. Histology shows stratified squamous epithelium in a whorling pattern, wet keratin nodules, and dystrophic calcification. This tumour arises from remnants of:
60. A 40-year-old woman undergoes adrenalectomy for Conn's syndrome (primary hyperaldosteronism). Histology shows a yellow-coloured adrenal cortical adenoma composed of lipid-laden cells resembling zona fasciculata. The zona glomerulosa cells in primary aldosteronism show which change in the contralateral adrenal gland?
61. A 50-year-old man with MEN2B has medullary thyroid carcinoma (MTC). MTC arises from which thyroid cell type and secretes which marker?
62. The classic nuclear features of papillary thyroid carcinoma (PTC) include Orphan Annie eye nuclei and nuclear grooves. The molecular mechanism underlying most sporadic PTCs involves constitutive activation of which signalling pathway?
63. A patient with MEN1 syndrome (menin mutation) develops primary hyperparathyroidism from parathyroid hyperplasia, pancreatic neuroendocrine tumours, and a pituitary adenoma. Menin normally functions as:
64. Adrenal cortical carcinoma (ACC) is distinguished from adrenal cortical adenoma using the Weiss scoring system. Which histological feature carries the highest discriminatory weight?
65. A 35-year-old woman has a thyroid nodule. Fine-needle aspiration shows cells with nuclear grooves, optically clear nuclei ('Orphan Annie eye'), and nuclear pseudo-inclusions. The most likely diagnosis is:
66. A 40-year-old man is found to have bilateral adrenal masses and episodic hypertension. Urine catecholamines are elevated. Adrenal tissue removed at surgery shows cells arranged in 'Zellballen' (ball-like nests) with sustentacular cells at the periphery. This histological pattern is characteristic of:
67. Waterhouse-Friderichsen syndrome results in adrenal insufficiency by which pathological mechanism?
68. A 28-year-old woman with Graves disease has a diffusely enlarged thyroid. The pathological finding on histology that reflects the effect of TSH receptor-stimulating antibodies is:
69. Multiple endocrine neoplasia type 2A (MEN2A) is caused by germline gain-of-function mutations in the RET proto-oncogene and includes medullary thyroid carcinoma (MTC), pheochromocytoma, and primary hyperparathyroidism. MTC arises from which thyroid cell type?
70. A 55-year-old man is diagnosed with a pituitary adenoma secreting GH. The somatotroph adenoma is most reliably distinguished from a normal pituitary on histology by:
71. A 40-year-old woman presents with a thyroid nodule. FNAC shows papillary carcinoma. Histology confirms orphan Annie eye nuclei, nuclear grooves, and psammoma bodies. The most common oncogenic driver in sporadic papillary thyroid carcinoma is:
72. A 40-year-old man presents with hypertension, hypokalemia, and suppressed plasma renin activity. CT shows a 1.5 cm right adrenal adenoma. The biochemical hallmark confirming primary hyperaldosteronism is:
73. Papillary thyroid carcinoma (PTC) is characterised by the nuclear features of Orphan Annie eye nuclei, nuclear grooves, and nuclear pseudoinclusions. The most common molecular alteration driving PTC is:
74. A 35-year-old woman undergoes adrenalectomy for a 4-cm adrenocortical mass. Histological features predicting malignancy include high mitotic rate, atypical mitoses, venous invasion, capsular invasion, and necrosis. These criteria are scored using the:
75. Waterhouse-Friderichsen syndrome is acute adrenal insufficiency caused by massive bilateral adrenal hemorrhage. The most common organism responsible for this syndrome is:
76. Papillary thyroid carcinoma is the most common thyroid malignancy. Which histological features are PATHOGNOMONIC of papillary carcinoma, even in the absence of papillae?
77. Papillary thyroid carcinoma shows characteristic nuclear features that include all of the following EXCEPT:
78. A 30-year-old woman with episodic hypertension, palpitations, and sweating has an adrenal mass. The tumor stains positively for chromogranin A and synaptophysin. Microscopically, cells are arranged in 'Zellballen' (cell balls). Which SDH subunit mutation, when present, specifically indicates hereditary paraganglioma-pheochromocytoma syndrome with risk of malignancy?
79. A 35-year-old woman undergoes thyroidectomy for papillary thyroid carcinoma showing Orphan Annie eye nuclei, nuclear grooves, pseudoinclusions, and psammoma bodies. The most common molecular alteration in sporadic PTC is:
80. A 45-year-old man has hypertension, hypokalemia, and metabolic alkalosis. Adrenal CT shows a 1.8 cm left adrenal adenoma. Aldosterone-to-renin ratio is markedly elevated. The pathological adrenal cortical zone from which this adenoma arises is:
81. A 30-year-old woman has amenorrhea and galactorrhea. MRI shows a 6 mm pituitary lesion. Serum prolactin is 320 ng/mL. The most likely pathological diagnosis and expected IHC finding are:
82. A 35-year-old woman undergoes thyroidectomy for a 2.5 cm solitary thyroid nodule. Histology shows follicular patterned cells with nuclear features including nuclear clearing, nuclear grooves, and pseudoinclusions. There is capsular and vascular invasion. Which thyroid carcinoma is this?
83. A 28-year-old woman undergoes thyroidectomy for bilateral thyroid nodules. Histology shows sheets of polygonal cells with abundant granular eosinophilic cytoplasm (oncocytic cells), round nuclei, and central nucleoli. Calcitonin immunostain is negative; thyroglobulin is positive. Congo red shows amyloid stroma is ABSENT. Electron microscopy would show mitochondria-packed cytoplasm. What is the diagnosis?
84. A patient with MEN1 syndrome (menin mutation) is most likely to develop which combination of endocrine tumors?
85. A 30-year-old patient presents with episodic headache, sweating, palpitations, and hypertension. 24-hour urine shows markedly elevated catecholamines and metanephrines. CT scan shows a 4 cm right adrenal mass. Histological examination of the resected specimen cannot reliably distinguish benign from malignant pheochromocytoma based on:
86. Papillary thyroid carcinoma (PTC) has which specific nuclear features that are diagnostic on fine needle aspiration cytology?
87. In Waterhouse-Friderichsen syndrome, bilateral adrenal hemorrhage leads to acute adrenal insufficiency. The most common causative organism is:
88. A pituitary adenoma causing acromegaly secretes excess growth hormone. Which type of pituitary cell (by immunohistochemistry) produces growth hormone?
89. A 40-year-old woman undergoes thyroid surgery for a cold nodule. Histology shows follicular cells arranged in papillary fronds with fibrovascular cores. The nuclei show 'Orphan Annie eye' (clear/ground-glass) chromatin, nuclear grooves, and intranuclear pseudoinclusions. Psammoma bodies are present. Which molecular finding is most commonly identified in this tumor?
90. A 35-year-old man has episodic headaches, sweating, and hypertension with blood pressure reaching 220/130 mmHg during attacks. Plasma free metanephrines are markedly elevated. CT scan shows a 4 cm adrenal mass. The histological hallmark used to distinguish benign from malignant pheochromocytoma is:
91. A 45-year-old woman presents with menstrual irregularity, galactorrhea, and bitemporal hemianopia. MRI shows a 15 mm sellar mass with suprasellar extension. Serum prolactin is 3200 ng/mL. The first-line treatment for this condition is:
92. A 40-year-old woman with a thyroid nodule undergoes fine-needle aspiration cytology. Cytology shows ground-glass 'Orphan Annie eye' nuclei, nuclear grooves, and pseudoinclusions. BRAF V600E mutation is detected on molecular testing. What is the diagnosis and the mechanism by which BRAF V600E drives carcinogenesis?
93. A 35-year-old woman with hypertension, hypokalaemia, and elevated plasma aldosterone-to-renin ratio undergoes adrenal CT showing a 1.5 cm right adrenal adenoma. Pathology of the resected adenoma shows pale, lipid-laden 'clear cells' with abundant cytoplasm and small nuclei. Which zone of the adrenal cortex does this adenoma recapitulate?
94. Multiple endocrine neoplasia type 2A (MEN2A) is associated with RET proto-oncogene mutations causing medullary thyroid carcinoma, phaeochromocytoma, and parathyroid hyperplasia. In MEN2A-associated medullary thyroid carcinoma, what is the staining characteristic that confirms calcitonin-secreting C-cell origin?
95. Papillary thyroid carcinoma is the most common thyroid malignancy. The MOST specific histological diagnostic feature (even in metastatic lymph nodes) is:
96. Waterhouse-Friderichsen syndrome is characterized by bilateral adrenal hemorrhage and acute adrenal insufficiency. The most common causative organism is:
97. Pheochromocytoma follows the 'rule of 10s.' Which of the following correctly represents this mnemonic?
98. A patient presents with bitemporal hemianopia, headache, and growth hormone excess. MRI shows a sellar mass extending into the suprasellar region. The pathological diagnosis is most likely:
99. A 42-year-old woman has a thyroid nodule biopsied. Cytology shows 'Orphan Annie eye' nuclei (ground-glass nuclei with cleared chromatin), nuclear grooves, and psammoma bodies. Which is the most likely diagnosis?
100. A 25-year-old man develops paroxysmal hypertension, diaphoresis, and palpitations. 24-hour urine shows markedly elevated catecholamines and metanephrines. Imaging reveals a 4 cm adrenal mass. This tumor arises from which cell type?
101. A patient with MEN1 syndrome develops a pituitary adenoma. Which of the following pituitary cell types is most commonly involved in functioning pituitary adenomas in MEN1?
102. Waterhouse-Friderichsen syndrome is a catastrophic complication primarily associated with which organism, and what is the underlying pathological process in the adrenal glands?
103. Papillary thyroid carcinoma (PTC) has the characteristic nuclear features known as 'Orphan Annie eye' nuclei. At the molecular level, the most common oncogenic driver event in PTC is:
104. Primary adrenal cortical insufficiency (Addison disease) in a 30-year-old woman shows bilateral adrenal enlargement on CT and serum 21-hydroxylase antibodies. Autoimmune destruction of the adrenal cortex is predominantly mediated by:
105. A 45-year-old woman has galactorrhea, amenorrhea, and MRI showing a 1.2 cm sellar mass. Serum prolactin is 280 ng/mL. The pathological basis of macroprolactinoma growth is primarily driven by:
106. Medullary thyroid carcinoma (MTC) is derived from parafollicular C cells and secretes calcitonin. On histology, the stroma characteristically contains:
107. A 45-year-old woman presents with a painless neck mass. Fine-needle aspiration shows cells with oval nuclei, pale powdery chromatin, nuclear grooves, and occasional intranuclear inclusions. Psammoma bodies are identified. Which molecular alteration is most characteristically associated with this tumor?
108. A 60-year-old man with a history of neck irradiation presents with a rapidly enlarging thyroid mass causing hoarseness and dysphagia. Biopsy shows sheets of highly pleomorphic cells with frequent mitoses, areas of tumor necrosis, and spindle cell components. The most likely diagnosis carries which prognosis?
109. A 38-year-old woman has elevated serum calcitonin and a thyroid nodule. Biopsy reveals nests and trabeculae of polygonal cells embedded in an amyloid-rich stroma that stains positively with Congo red. This tumor most commonly arises from which cell type?
110. A 55-year-old man with type 2 diabetes mellitus for 15 years undergoes renal biopsy for progressive proteinuria. Light microscopy shows nodular deposits of acellular, eosinophilic PAS-positive material in the glomerular mesangium. These deposits are eponymously named after which pathologist?
111. A 32-year-old woman presents with episodic hypertension, headache, diaphoresis, and palpitations. 24-hour urine shows markedly elevated catecholamines and their metabolites. CT reveals a 4 cm right adrenal mass. Histologically, this tumor is characterized by which feature that predicts malignancy?
112. A young man is found to have hyperparathyroidism, medullary thyroid carcinoma, and bilateral adrenal pheochromocytomas. Genetic testing reveals a germline gain-of-function mutation in the RET proto-oncogene. Which additional feature distinguishes his syndrome from MEN 2A?
113. A patient with MEN 1 syndrome is most likely to harbor a mutation in which gene, and which combination of tumors defines this syndrome?
114. A 28-year-old woman develops central obesity, hypertension, glucose intolerance, purple striae, and proximal muscle weakness. Morning serum cortisol is elevated and does not suppress with low-dose dexamethasone but suppresses with high-dose dexamethasone. The most likely pathology driving her symptoms is:
115. Autopsy of a 10-year-old child who died from Waterhouse-Friderichsen syndrome shows bilateral adrenal hemorrhagic necrosis. Which organism is the most common causative agent of this catastrophic complication?
116. A 40-year-old woman with Hashimoto thyroiditis develops progressive fatigue, weight gain, constipation, dry skin, and bradycardia. Thyroid biopsy performed years earlier showed which characteristic histologic feature that predicts this eventual functional outcome?
117. MEN2A (Multiple Endocrine Neoplasia type 2A) involves medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. The causative mutation is:
118. A 58-year-old man with a 30-pack-year smoking history undergoes elective coronary artery bypass surgery. During the procedure, the left anterior descending artery territory is subjected to 45 minutes of ischemia. Reperfusion is then established. On histological examination of the myocardium the following day, which ultrastructural finding is MOST characteristic of irreversible cell injury that occurred prior to reperfusion?
119. A 42-year-old woman presents with a painful boil on her right forearm. On examination there is a 2 cm fluctuant swelling with surrounding erythema and warmth. Aspiration yields creamy yellow pus. Histologically, the lesion shows a central zone of necrotic neutrophils and debris surrounded by a rim of proliferating fibroblasts and new blood vessels. Which of the following best describes the predominant pattern of necrosis at the center of this lesion?
120. A surgical pathologist examining a biopsy from a healing skin laceration (day 7 post-injury) identifies numerous fibroblasts, proliferating capillary loops, and a loose extracellular matrix. The new blood vessels in this tissue show which of the following characteristics compared with mature vessels?
121. During an autopsy of a 70-year-old man who died of cardiac failure, the pathologist notices that several organs show a pattern of atrophy where individual cells have shrunk and contain small, golden-brown cytoplasmic granules. The organ most prominently affected is the heart, giving it a small, dark brown appearance with prominent epicardial fat remaining. What is the PRIMARY component of these golden-brown granules?