Myopericytoma: a pleural-based spindle cell neoplasm off the beaten path.

Myopericytoma is a recently described hemangiopericytoma-like neoplasm with myoid differentiation. These tumors are typically located in the subcutaneous and soft tissues of the extremities. The authors report a rare pleural-based pulmonary myopericytoma in a 58-year-old woman. The lesion was grossly homogeneous and well circumscribed. Microscopically, it was composed of densely packed spindle cells organized as whorls and short interlacing fascicles with a concentric perivascular distribution. Immunohistochemical reactions were positive for vimentin, smooth muscle actin (SMA), muscle-specific actin, and Bcl-2 and negative for desmin, h-caldesmon, cytokeratin, and CD34. Atypically, increased mitotic activity was noted, but no other malignant features were identified. The differential diagnoses are discussed with specific emphasis on solitary fibrous tumor of the pleura, which is the most common benign pleural-based spindle cell neoplasm and may be a diagnostic pitfall with potentially harmful consequences.

Pleural mesothelioma: sensitivity and incidence of needle track seeding after image-guided biopsy versus surgical biopsy.

PURPOSE: To retrospectively compare the sensitivity of image-guided core-needle biopsy, thoracoscopy, and thoracotomy in the diagnosis of malignant pleural mesothelioma and to retrospectively determine the incidence of needle track seeding after these procedures. MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was not required. The study included 100 consecutive patients (81 men, 19 women; average age, 65.8 years) with pathologically proved malignant pleural mesothelioma who were treated between 1994 and 2002. A total of 23 core-needle biopsies were performed in 22 patients, and 11 of these biopsies were coupled with fine-needle aspiration biopsy. A coaxial technique was used, and biopsy was performed with fluoroscopic (12 biopsies), computed tomographic (10 biopsies), or ultrasonographic (one biopsy) guidance. Sixty-nine patients underwent surgical biopsy in the form of thoracoscopy (n = 51) and/or thoracotomy (n = 21). Patients were followed up clinically for any evidence of needle track seeding after image-guided or surgical procedures. The sensitivity of diagnostic procedures and the incidence of needle track seeding as a result of intervention were calculated. RESULTS: Sensitivity was 86% for image-guided core-needle biopsy, 94% for thoracoscopy, and 100% for thoracotomy. The incidence of needle track seeding was 4% for image-guided core-needle biopsy and 22% for surgical biopsy. CONCLUSION: Image-guided core-needle biopsy in patients with malignant pleural mesothelioma has a lower incidence of needle track seeding than surgical biopsy and has a high sensitivity for diagnosis.