Primary germ cell tumors of the mediastinum

Abstract

seminoma were reviewed, and the immunohistochemical staining patterns in 50 of these tumors were also analyzed. 1 Department of Pulmonary and Mediastinal Pa- RESULTS.The patients were all men between the ages of 14 and 79 years (mean thology, Armed Forces Institute of Pathology, age, 46.5 years). Their clinical symptoms included cough, chest pain, and dyspnea. Washington, DC.In some patients, the lesions were asymptomatic and discovered incidentally on 2 Arkadi M. Rywlin Department of Pathology and routine chest radiographs. None of the patients had a previous history of testicular Laboratory Medicine, Mount Sinai Medical Cenneoplasm or tumor elsewhere. Macroscopically, the tumors were described as soft ter and the University of Miami School of Mediand tan, with a slightly lobulated cut surface, and measured up to 16 cm in greatest cine, Miami, Florida.dimension. Histologically, the morphologic features were similar to those of tumors occurring in the gonads, namely, a neoplastic proliferation of round-to-polygonal cells with indistinct cell borders, clear-to-lightly-eosinophilic cytoplasm with roundto-oval nuclei and prominent nucleoli, associated with a prominent inflammatory background composed mainly of mature lymphocytes. Necrosis, hemorrhage, multinucleated giant cells, granulomatous reaction, and remnants of thymic tissue were observed in a variable number of cases; mitoses were rare. Immunohistochemical studies in 50 cases showed cytoplasmic staining with placental alkaline phosphatase in 80% of the tumors, focal dotlike positivity for CAM 5.2 low-molecular-weight keratins in 75%, focal cytoplasmic staining for wide-spectrum keratin in 70%, focal positive reaction with vimentin in 70%, and focal positivity with HCG in singly scattered cells in 5%. Immunostains for carcinoembryonic antigen, epithelial membrane antigen, and a-fetoprotein were negative in all the cases studied. Fifty patients were Stage I, 3 patients were Stage II, and 12 patients were Stage III. Clinical followup information was obtained for 65 cases (54%). Forty-nine patients were alive and disease free after a period ranging from 1 to 19 years (mean follow-up, 10 years). Sixteen patients died within the same period and were found to have metastases to distant organs. Of the 16 patients who died, 6 showed extension of the tumor outside of the mediastinal compartment at the time of initial diagnosis (Stage III lesions). Presented in part at the 85th annual meetingAside from clinical staging, the authors' findings also suggest that patients ú37 years of the United States and Canadian Academy of have worse outcomes than younger individuals. The authors were unable to find Pathology, Washington, DC, March 1996. any correlation between histopathologic features and clinical behavior in any of these cases. Address for reprints: Cesar A. Moran, M.D., De-

Treatment strategies and prognostic factors of patients with primary germ cell tumors in the mediastinum

“…Five-year overall survival rate of patients who had tumors localized at the mediastinum, metastasized to lungs or distant sites were 72%, 45%, and 0, respectively, P  = 0.005. We obtained an opinion which was agreed by previous experts that earlier diagnosis and treatments are key strategies to improving the therapeutic efficacies and overall survival of patients with primary mediastinal germ cell tumors (Moran et al 1997c). …”

Establishment and Characterization of a new Human Extragonadal Germ Cell Line, SEM-1, and its Comparison With TCam-2 and JKT-1

“…SEM-1 also demonstrated positive staining for CAM5.2, consistent with reports documenting positive expression of CAM5.2 in 80% of mediastinal vs 20% of testicular seminoma. 20,22 Although SEM-1 did not show increased expression of PLAP by qRT-PCR or M2A by immunohistochemistry, there was increased expression of AP-2γ, which has been shown to be of value in the detection of extragonadal seminoma specifically. 15,17,21 Stem cell markers OCT3/4, NANOG, and c-KIT showed heterogeneous expression in SEM-1, indicating that there may be multiple subclones present with features characteristic of both seminomatous and nonseminomatous tumors.…”

“…18,19 Finally, recent reports suggest that extragonadal seminomas may represent a more mature phenotype characterized by the expression of the same markers and increased expression of PLAP, cytokeratin CAM5.2 (cytokeratin 8/18), vimentin, AP-2γ, and M2A when compared with testicular seminomas. 20–22 …”

Thymoma and Synchronous Primary Mediastinal Seminomas with Florid Follicular Lymphoid Hyperplasia in the Anterior Mediastinum: A Case Report and Review of the Literature

“…Germ cell tumors (GCTs) of the mediastinum are also uncommon in adults and account for 10% to 20% of anterior mediastinal tumors [1-3]. Teratomas are the most common mediastinal GCTs, accounting for 44% of all mediastinal GCTs, and seminomas are the second most common, with an incidence of approximately 37% [4]. Thymomas occur most frequently in adults between the ages of 55 and 65 years, and thus, they are exceedingly rare in children and adolescents.…”

“…Fortunately, mediastinal GCTs can be associated with secondary changes that are rarely found in testicular or ovarian tumors. These changes include reactive proliferation of remnant thymic epithelium, multiple cystic formations, epithelioid granulomatous reactions, fibrosis, and follicular lymphoid hyperplasia [4,7,9-11]. To the best of our knowledge, the simultaneous occurrence of thymomas and seminomas in the thymus has not been previously reported.…”