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[This corrects the article DOI: 10.3892/mco.2018.1630.].
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Following breast and lung cancers, renal cell carcinoma (RCC) is the third most frequent cancer to metastasize to the head and neck region, though such cases are rarely reported. Distinguishing between malignant tumors of salivary gland origin and metastatic RCC is very important. The case of a 75-year-old man with an oral cavity lesion in the left buccal submucosa measuring 40×30 mm that had grown substantially over several weeks is presented. His medical history included left kidney cancer 26 years earlier and a malignant myoepithelioma of the left buccal region 7 years earlier. It was suspected that this lesion was a recurrent malignant myoepithelioma as it appeared at the same site as the previous operation. Surgery was performed, and metastatic RCC was confirmed upon pathological examination. The diagnosis of metastatic RCC was made by immunohistochemical examination, which also excluded malignant myoepithelioma and other clear cell carcinomas of salivary gland origin. Metastatic RCC must be considered in the differential diagnosis of a new oral cavity lesion presenting in a patient with a past history of kidney cancer. Thus, immunohistochemical staining is required to distinguish malignancies of salivary gland origin, including malignant myoepithelioma, from metastatic RCC.
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BACKGROUND: Although the histologic features of malignant peripheral nerve sheath tumor (MPNST) have been described, the cytologic features of primary pulmonary MPNST have not been reported in the literature. CASE: We report a case of primary pulmonary MPNST in a 78-year-old man. Follow-up computed tomography of colon cancer, renal cancer, penile cancer and gingival cancer revealed a nodular lesion, 12 mm in diameter, in the right upper lobe of the lung. In frozen section, a diagnosis of malignant neoplasm, not otherwise specified, was rendered for the imprinting specimen and histologic specimen. Imprinting specimens were composed of small cellular aggregates and discohesive neoplastic cells with obvious malignant features. Histologically, spindle cells with pleomorphic nuclei arranged infascicular patterns and multinucleated tumor giant cells were also observed. More than 25 mitotic figures were observed per 10 high-power fields. Tumor cells were positive only for vimentin and S-100, and the Ki-67 labeling index was 10%. Clinical and imaging investigation failed to identify an alternative primary site. We histologically diagnosed this case as primary pulmonary MPNST. CONCLUSION: MPNST has a varied cytomorphology with frank nuclear atypia showing no definite differentiation. Multinucleated neoplastic giant cells with immunopositivity for S-100 may permit more accurate diagnosis of MPNST.