Introduction
Extragonadal germ cell tumors are rare and comprise a heterogeneous group of neoplasm1. Somatic transformation occurs in 2% of GCT and it is even rarer in extragonadal sites2. The exact pathogenic mechanism is unknown. The prognosis is unfavorable because cisplatin-based chemotherapy is not effective2. Surgical resection is the mainstay of the treatment.
Case report
A 26- year-old male presented with cough, shortness of breath, fever. Chest CT revealed a mass 10 cm in size at the level of 3rd -8th ribs. Right-sided pleural effusion was noted. Histologic evaluation revealed pure seminoma. Serum markers were elevated. The patient received 4 cycles of chemotherapy with BEP regimen. Serum markers decreased to baseline.PET/CT done after 4 months since diagnosis showed a reduction in the size of the tumor. Gross tumor volume was irradiated. Upon restaging, PET /CT showed a complete metabolic response. Chest CT done 3 years thereafter showed an anterior mediastinal mass 52 mm in size. PET/CT confirmed the presence of a mass lesion consistent with the recurrence of the primary disease. Chemotherapy was initiated with a VIP regimen. The mass decreased in size. Radical resection of the tumor was done. The tissue was positive for vimentin and negative for PanCK, EMA, S-100, desmin, C-kit, PLAP, HCG, Ki 67 -50%. The diagnosis of pleomorphic sarcoma was made.
Follow up CT after 4 months showed recurrence. The decision was made to initiate chemotherapy with docetaxel/gemcitabine.
Conclusion
The occurrence of somatic type malignancy in germ cell tumors is rare. The reported case is unique because of the location and histology of the primary tumor. Our case confirms that transformed tumors do not respond to GTM-based chemotherapy regimens and surgery is the mainstay of the therapy.
References
1. Dieckmann KP, Anheuser P, Gehrckens R, Wilczak W, Sauter G, Höflmayer D. Pure Testicular Seminoma Relapsing Late with Somatic Type Malignancy. Case Rep Oncol Med. 2017;2017:2457023. doi:10.1155/2017/2457023
2. O. El Mesbahi, M.-J. Terrier-Lacombe, C. Rebischung, C. Theodore, D. Vanel, and K. Fizazi, “Chemotherapy in patients with teratoma with malignant transformation,” EuropeanUrology,vol.51,no.5,pp.1306–1312,2007