Primary thymic neuroblastomas in adults: A clinicopathological and immunohistochemical study of three cases.

Three cases of primary neuroblastomas presenting as anterior mediastinal tumors are presented. The patients are two women and one man between the ages of 57 and 63 year. Clinically, the patients presented with symptoms of chest pain, cough, and shortness of breath. Diagnostic imaging revealed the presence of an anterior mediastina mass. Initial biopsy was non-diagnostic in two patients, while in one patient no biopsy was obtained. Surgical resection via thoracotomy was performed in all three patients. Grossly, the tumors vary in size from 3 to 4.5 cm in greatest dimension, and they were described as well circumscribed but not encapsulated, light brown in color. Areas of hemorrhage and/or necrosis were not described. Histologically, at low power the tumors were surrounded by a rim of adipose tissue containing remnants of thymic tissue with Hassall's corpuscles. At higher magnification, the tumors show the characteristic small round cell proliferation with varying amounts of neurophil. Mitotic activity was present but not in large number. Areas of necrosis and/or hemorrhage were not identified. Immunohistochemically, the tumors show positive staining for NSE, while synaptophysin highlighted neurophil. Other markers epithelial and neuroendocrine were negative. Clinical follow-up information shows that two patients have remained alive 8 and 12 months after initial surgical resection. One patient was lost to follow-up.