Presentation
2 month history of focal scalp tenderness following trauma. Imaging revealed a focal lesion, but 1 week prior to surgery, the pain resolved and further scans were obtained. Past history of sarcoidosis currently in remission
Patient Data
Focal well defined lytic lesion with some peripheral mineralization in the right parietal bone noted. On SPECT it demonstrates increased uptake on delayed sequences, but no increase on dynamic or bloodpool images.
Single slices from digitized printed films from another institution demonstrate the lesion to be of high T2 signal which does not suppress on FLAIR. It has intermediate T1 signal with avid contrast enhancement. Only intermediate restricted diffusion.
MICROSCOPIC DESCRIPTION:
Sections of the bone show an area of loose fibrous tissue with edema in the medulla. There are several aggregates of epithelioid cells with large indented vesicular nuclei, intranuclear grooves and prominent nucleoli in a background of lymphocytes, plasma cells, pigment-laden macrophages and occasional multinucleated giant cells. Eosinophilia is not a feature. No granulomas are present. Atypical mitoses are not seen. The overall features are suggestive of Langerhans' cell histiocytosis. However, these clusters of epithelioid cells have cut-out on the immunostained slides and therefore, the diagnosis cannot be confirmed.
FINAL DIAGNOSIS: Morphological features suggestive of Langerhans' cell histiocytosis.
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