FINE-NEEDLE ASPIRATION OF POORLY DIFFERENTIATED RHABDOMYOSARCOMA PRESENTING WITH QUADRIPARESIS - A CASE-REPORT

BACKGROUND: The diagnosis of metastatic poorly differentiated rhabdomy osarcoma (RMS) in lymph node specimens by fine needle aspiration prese nts a difficult problem since it is virtually indistinguishable from o ther small round cell neoplasms. CASE: Fine needle aspiration was perf ormed under radiologic guidance on an extradural, space-occupying lesi on of unknown etiology in the region of the C-6 and C-7 vertebrae in a 20-year-old male who was hospitalized with quadriparesis. Cytologic e xamination suggested a metastatic tumor consistent with the diagnosis of rhabdomyosarcoma. A subsequent search for the primary tumor site re vealed a soft tissue swelling in the right calf muscle. Light microsco pic, ultrastructural and immunocytochemical examination of multiple Tr u-cut biopsy specimens from the swelling in the right calf muscle conf irmed the diagnosis of poorly differentiated embryonal rhabdomyosarcom a. CONCLUSION: Immunostaining is useful for muscle proteins in the det ection of poorly differentiated forms of embryonal rhabdomyosarcoma. E lectron microscopy is of limited use in such eases.