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Langerhans Cell Histiocytosis — MFDS Part 1 MCQ

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HardOral PathologyLangerhans Cell HistiocytosisMFDS Part 1

A 9-year-old child presents with rapidly progressive mobility of several mandibular teeth. Imaging demonstrates multifocal, sharply demarcated osteolytic lesions of the alveolar bone. Biopsy shows sheets of histiocyte-like cells with reniform, longitudinally grooved nuclei admixed with numerous eosinophils. Which additional pathological finding would most specifically support a diagnosis of Langerhans cell histiocytosis?

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Correct answer: D — Lesional histiocytes coexpressing CD1a and CD207 (langerin)

The correct answer is D. Multifocal jaw osteolysis, tooth mobility and an eosinophil-rich infiltrate of histiocytes with grooved, reniform nuclei are characteristic of Langerhans cell histiocytosis. Demonstration that the lesional histiocytes coexpress CD1a and CD207 (langerin) provides specific diagnostic support. CD207 is associated with formation of Birbeck granules, but these granules require electron microscopy and are not a routine histological finding. Touton giant cells with CD1a-negative foamy histiocytes suggest a non-Langerhans histiocytosis. Reed–Sternberg cells indicate classical Hodgkin lymphoma. Aschoff bodies occur in rheumatic carditis, while caseating granulomas with Langhans-type giant cells suggest a granulomatous infection such as tuberculosis.

Reference: Bielamowicz K et al. Langerhans cell histiocytosis: NACHO update on progress, chaos, and opportunity on the path to rational cures. Cancer. 2024;130(14):2416–2439. https://pubmed.ncbi.nlm.nih.gov/38687639/