Review Question - QID 210898

This patient with diabetes insipidus, a scalp rash, and lytic skull lesions most likely has Hand-Schüller-Christian disease, which is a Langerhans cell histiocytosis disorder that presents with tennis racket-shaped granules on electron microscopy.

Langerhans cell histiocytoses are a class of disorders that demonstrate proliferation of dendritic (Langerhans) cells from the monocyte lineage. These cells normally present antigens to T-cells and characteristically have Birbeck granules, which are cytoplasmic rod-shaped granules with a terminal expansion and latticed matrix that can be seen on electron microscopy. These granules are often described as having a tennis racket appearance. In particular, Hand-Schüller-Christian disease presents in adolescence and manifests with scalp rash, diabetes insipidus, lytic skull lesions, and exophthalmos though most patients do not have all four classic symptoms.

Incorrect Answers:
Answer 1: Anti-nuclear antibodies on serology is seen in a variety of autoimmune diseases include lupus; however, they would not be seen in Langerhans cell histiocytoses.

Answer 3: HLA-B27 gene variant on genetic testing is associated with psoriasis as well as other inflammatory disorders; however, this gene variant is not associated with Langerhans cell histiocytoses.

Answer 4: Neoplastic CD2+ and CD4+ cells on serology would be seen in cutaneous T-cell lymphoma as well as T-cell leukemias; however, these cells are not found in Langerhans cell histiocytoses.

Answer 5: Noncaseating granulomas with multinucleated giant cells on histology would be seen in sarcoidosis; however this finding would not be seen in Langerhans cell histiocytoses.

Bullet Summary:
Tennis racket-shaped Birbeck granules are seen on electron microscopy in Langerhans cell histiocytoses.