Primary pulmonary malignant peripheral nerve sheath tumor: a case report.
BACKGROUND: Although the histologic features of malignant peripheral nervesheath tumor (MPNST) have been described, the cytologic features of primary pulmonary MPNST have notbeen reported in the literature. CASE: We report a case of primary pulmonary MPNST in a 78-year-oldman. Follow-up computed tomography of colon cancer, renal cancer, penile cancer and gingival cancerrevealed a nodular lesion, 12 mm in diameter, in the right upper lobe of the lung. In frozensection, a diagnosis of malignant neoplasm, not otherwise specified, was rendered for the imprintingspecimen and histologic specimen. Imprinting specimens were composed of small cellular aggregatesand discohesive neoplastic cells with obvious malignant features. Histologically, spindle cells withpleomorphic nuclei arranged infascicular patterns and multinucleated tumor giant cells were alsoobserved. More than 25 mitotic figures were observed per 10 high-power fields. Tumor cells werepositive only for vimentin and S-100, and the Ki-67 labeling index was 10%. Clinical and imaginginvestigation failed to identify an alternative primary site. We histologically diagnosed this caseas primary pulmonary MPNST. CONCLUSION: MPNST has a varied cytomorphology with frank nuclear atypiashowing no definite differentiation. Multinucleated neoplastic giant cells with immunopositivity forS-100 may permit more accurate diagnosis of MPNST.
Tashiro,T　Kawakita,C　Takai,C　Yoshida,T　Sakiyama,S　Kondo,K　Sano,N
Pathology Division, Hyogo Prefectural Kakogawa Hospital, Hyogo, Japan.kenkako1@gold.ocn.ne.jp
Aged　 Cell Nucleus　 Giant Cells　 Humans　 Lung Neoplasms　 Male Nerve SheathNeoplasms
