A bone biopsy from a patient with osteomalacia is examined under polarized light after tetracycline labeling. The hallmark histological finding is:

• A Increased osteoclast number with Howship's lacunae and fibrous replacement of marrow
• B Mosaic pattern of lamellar bone with irregular cement lines and disorganized collagen architecture
• C Thinned trabeculae with reduced osteoid volume and normal mineralization fronts
• D Excessive unmineralized osteoid with widened osteoid seams and decreased mineralization lag time ✓

Explanation

Osteomalacia is defined by defective mineralization of bone matrix, resulting in accumulation of unmineralized osteoid. Widened osteoid seams and decreased mineralization rate on tetracycline labeling are diagnostic. Option A describes Paget's disease. Option C describes osteoporosis. Option B describes the mosaic pattern of Paget's disease.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.