Papillary renal cell-like carcinoma in a retroperitoneal teratoma

Papillary Renal Cell Carcinoma Arising in a Lymph Node Metastasis of a Testicular Teratoma: A Very Rare Occurrence

We present a case of a teratoma with somatic type malignancy (TSM) in the form of papillary renal cell carcinoma (pRCC) within supraclavicular and retroperitoneal lymph node metastases of a testicular pure teratoma. Resection of both masses revealed a teratoma without any other germ cell tumor component. A papillary carcinoma component was also detected intermingled with the teratomatous elements. The carcinoma cells displayed eosinophilic cytoplasm and prominent nucleoli. Groups of foamy histiocytes in the fibrovascular cores was a striking finding that brought pRCC to mind. Immunoreactivity for CK7, PAX8, AMACR, CD10, napsin, and vimentin along with morphologic findings confirmed renal cell differentiation. No radiological evidence of a primary renal cell carcinoma was found in the kidney. Consequently, pRCC arising in a teratoma was diagnosed. TSM is described as teratoma with a malignant component that is typically encountered in other organs and tissues. TSM in the form of pRCC is an extremely rare entity. Our case is the second example of a testicular germ cell tumor metastasis with a somatic malignancy in the form of pRCC. In conclusion, carcinomas of renal cell differentiation should be kept in mind as a rare form of TSM, especially in metastatic germ cell tumors.

Primary retroperitoneal mature cystic teratoma with focal enteric type adenocarcinoma in a post-partum woman: report of a case with literature review

Teratomas are characterized by containing tissue from all three germinal cell layers. Occasionally, somatic type malignancies develop within a mature cystic teratoma. We reported here a rare case of enteric type adenocarcinoma, with associated dysplastic epithelial precursor lesion, arising within a mature cystic teratoma in the retroperitoneum of a 30-year-old woman status post vaginal delivery 11 weeks earlier. The mass is 17.5 cm and cystic. A polypoid mass component measuring 4.7×4.2×2.5 cm was located inside the cystic component. Microscopically, the majority of the specimen was a mature cystic teratoma with all three germinal cell layers. The polypoid mass component was an adenocarcinoma with an adjacent dysplastic epithelial precursor lesion. The adenocarcinoma was diffusely positive for CK20 and CDX-2, and focally positive for CD7, indicating enteric differentiation. A brief review of retroperitoneal mature cystic teratomas with associated somatic type malignancy was performed.

Retroperitoneal teratoma with somatic malignant transformation: a papillary renal cell carcinoma in a testicular germ cell tumour metastasis following platinum-based chemotherapy

Background

Malignant transformation describes the phenomenon in which a somatic component of a germ cell teratoma undergoes malignant differentiation. A variety of different types of sarcoma and carcinoma, all non-germ cell, have been described as a result of malignant transformation.

Case presentation

A 33-year-old man presented with a left testicular mass and elevated tumour markers. Staging investigations revealed retroperitoneal lymphadenopathy with obstruction of the left ureter and distant metastases. Histopathology from the left radical orchiectomy showed a mixed germ cell tumour (Stage III, poor prognosis). The ureter was stented and four cycles of cisplatin, etoposide and bleomycin chemotherapy administered. After initial remission, the patient recurred four years later with a large retroperitoneal mass involving the renal vessels and the left ureter. Left retroperitoneal lymph node dissection with en-bloc resection of the left kidney was performed.

Histopathology revealed a germ cell tumour metastasis consisting mainly of mature teratoma. Additionally, within the teratoma a papillary renal cell carcinoma was found. The diagnosis was supported by immunohistochemistry showing positivity for AMACR, CD10 and focal expression of RCC and CK7. There was no radiological or histo-pathological evidence of a primary renal cell cancer.

Conclusions

To the best of our knowledge, malignant transformation into a papillary renal cell carcinoma has not been reported in a testicular germ cell tumour metastasis following platinum-based chemotherapy. This histological diagnosis might have implications for potential future therapies. In the case of disease recurrence, renal cell cancer as origin of the recurrent tumour has to be excluded because renal cell carcinoma metastases would not respond well to the classical germ cell tumour chemotherapy regimens.

Teratoma with somatic-type malignant components of the testis. A review and an update

Malignant transformation of germ cell tumors into somatic malignancy is uncommon. Its presentation differs from series to series, with 43 % of adult cases identified within the primary tumors and the remainder at the time of relapse or in the metastasis. Patients with stage I disease enjoy an excellent prognosis; whereas in metastatic sites when not completely resectable, the somatic type malignancies suffer a dismal prognosis. Radical surgery is significant for the prospects of cure and is standard chemotherapy for germ cell tumors; a transformation-oriented treatment can be effective for these patients. A deeper understanding of the biology of this phenomenon is essential for clinicians involved in such malignancies in order to permit a better control of the disease.