| Abstract|| |
Testicular germ cell tumors (GCT) are a diverse group of neoplasms, broadly divided into seminomatous and non seminomatous types, with varying histomorphology. Mixed germ cell tumors express more than one germ cell component. Somatic type malignancy occurring in testicular GCT is rare. Most often these components present as metastasis, particularly following chemotherapy, rather than primarily involving the testis. We describe a rare case of a young adult with no significant past history, who presented with testicular mass which on histology revealed a non-seminomatous mixed germ cell tumor with additional somatic type malignancy component of a rhabdomyosarcoma.
Keywords: Germ cell tumors, somatic type malignancy, testis
|How to cite this article:|
Kothiya M, Bhandare S, Khubchandani S. Non seminomatous mixed germ cell tumor of the testis with predominant component of somatic type malignancy (Rhabdomyosarcoma) – A rare occurrence. Indian J Pathol Microbiol 2020;63:125-7
|How to cite this URL:|
Kothiya M, Bhandare S, Khubchandani S. Non seminomatous mixed germ cell tumor of the testis with predominant component of somatic type malignancy (Rhabdomyosarcoma) – A rare occurrence. Indian J Pathol Microbiol [serial online] 2020 [cited 2020 Sep 21];63:125-7. Available from: http://www.ijpmonline.org/text.asp?2020/63/1/125/277426
| Introduction|| |
Testicular germ cell tumors (GCT), diseases of the adolescent and young adults, are broadly classified as seminomatous and non-seminomatous type. Mixed GCTs reveal more than one type of germ cell tumor component. Testicular GCT with somatic type malignancy is a rare phenomenon and literature reports only 3-6% of all testicular GCT's showing these components. Most cases of somatic type malignancy have teratomatous GCTs. More often, somatic type malignancy component present as metastatic deposits, involving lymph nodes, particularly in setting of testicular GCT treated with chemotherapy. We describe a case of 25 year old male who presented with testicular mass which was diagnosed as mixed non seminomatous germ cell tumor with a somatic type malignancy component, the latter, being rhabdomyosarcoma.
| Case Report|| |
A 25-year-old male with no significant past history presented with pain and swelling of the left scrotum for a period of 2 weeks. Serum tumor markers (βHCG, AFP and LDH) were within normal limits. He subsequently underwent a sonography, which revealed a 5.8 × 4 cm sized complex solid focally cystic mass involving the left testis. The opposite side testis and bilateral epididymides were unremarkable. No other lesion was detected elsewhere.
The patient was subjected to a high left inguinal orchidectomy. The specimen showed an intact tunica. The cut surface revealed a soft yellowish white 5.5 × 5 × 2.5 cm tumor showing glistening myxoid areas alternating with few cystic areas filled with clear fluid [Figure 1]. The tumor was entirely confined to the testis. The histology showed a mixed non-seminomatous germ cell tumor composed of a teratoma (tubular structures lined by columnar vacuolated cells resembling gastrointestinal lining and islands of cartilage) [Figure 2]a, embryonal carcinoma [Figure 2]b and a rather predominant component of elongated, spindly to oval tumor cells with abundant eosinophilic cytoplasm (rhabdomyosarcomatous morphology) [Figure 2]c and [Figure 2]d. These cells showed mild to moderate nuclear pleomorphism and few mitotic figures [Figure 2]e and [Figure 2]f. The stroma was myxoid. A rim of compressed testicular parenchyma was noted at the periphery. The capsule of the testis was intact. The tunica albuginea, vaginalis, epididymis and spermatic cord were free of tumor involvement.
|Figure 1: Yellowish white tumor with glistening myxoid and few cystic areas, tumor is seen confined within the testis|
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|Figure 2: (a) Teratomatous tumor component with gastrointestinal lining like structure and island of cartilage, ×4; (b) embryonal carcinoma component, ×20; (c and d) rhabdomyosarcomatous component with oval to spindle-shaped cells with abundant eosinophilic cytoplasm embedded in myxoid stroma, ×10; (e and f) pleomorphism and mitotic activity in rhabdomyosarcomatous area, multinucleated cell, ×40|
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Immunohistochemistry revealed CD30 highlighting the embryonal carcinoma component while AFP was negative. Rhabdomyosarcomatous appearing tumor cells were diffusely positive for desmin [Figure 3]a and myogenin [Figure 3]b. Ki-67 proliferation index was 35-40% in the rhabdomyosarcomatous areas [Figure 3]c. PHH3 highlighted 7-8 mitotic figures/10 high power field [Figure 3]d.
|Figure 3: (a) Desmin highlighting rhabdomyosarcomatous component, ×10; (b) myogenin highlighting rhabdomyosarcomatous component, ×10; (c) Ki-67 proliferation index in rhabdomyosarcomatous component, ×40; (d) PHH3 demonstrating mitotic activity in spindly oval cells, ×40|
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The teratomatous component comprised 10% of the tumor, embryonal carcinoma was 5%, and the rest of the mass was the rhabdomyosarcoma component, accounting for 85% of the tumor. Thus, based on histology and immunohistochemistry (IHC) the final diagnosis was mixed non-seminomatous germ cell tumor (embryonal carcinoma 5% and teratoma 10%) with somatic type malignancy (rhabdomyosarcoma 85%), since the majority of the tumor was composed of the rhabdomyosarcomatous elements.
| Discussion|| |
Testicular GCT with somatic type malignancy is a rare occurrence. It is defined as atypical mesenchymal or epithelial component occupying at least one low power field (4× objective). Most of these are associated with a teratomatous germ cell component., The most common type of somatic malignancies are sarcomas, with rhabdomyosarcoma being the commonest subtype. Other types of somatic malignancies noted are carcinomas (adenocarcinoma being commonest amongst carcinoma), primitive neuroectodermal tumors and other types of sarcomas. Few hypotheses have been proposed regarding origin of the somatic malignancy in the germ cell tumors, like malignant transformation of the teratomatous component or aberrant dedifferentiation of the primitive germ cells. The index case had predominant areas of spindle to oval-shaped cells with abundant eosinophilic cytoplasm and mild to moderately pleomorphic hyperchromatic nuclei (rhabdomyosarcomatous morphology). This somatic type malignancy component usually presents at metastatic site, more often after chemotherapy. Our patient did not receive any chemotherapy prior to surgery.
The challenge we found in this case was that rhabdomyosarcomatous areas morphologically were not overtly malignant, mitotic activity was around 7-8/10 high power field and there was no necrosis. However, this component formed the major bulk of the tumor with Ki-67 proliferation index around 35-40% in the areas containing the spindle-shaped cells.
Furthermore, it is extremely important to recognize these sarcomatous components correctly as the chemosensitivities of pure GCT and GCT with somatic type malignancy are dissimilar. Pure GCT respond well to cisplatin based chemotherapy whereas somatic type malignancy component do not respond to the same. Treatment guidelines are not uniform for treating GCT with somatic type malignancy. Pham et al., recently described challenges in treating a case of paediatric patient with mixed non seminomatous GCT with rhabdomyosarcoma.
Virtually, all GCTs have increased copy number of chromosome 12p, either as isochromosome 12p [i(12p)] or tandem duplication of 12p. Transformed malignant component also harbours this 12p chromosomal abnormality, and in addition, displays cytogenetic or molecular characteristics of the specific transformed type. Primary rhabdomyosarcoma does not show i(12p) seen in GCTs. We could not perform any molecular analysis on the tumor tissue of our patient.
| Conclusion|| |
Testicular GCT with somatic type malignancy is rare, especially in patients who have not received chemotherapy, like the index case. The rhabdomyosarcomatous component in our case was morphologically immature and not overtly malignant. However, this component formed the major proportion of the tumor and had a high proliferation index. It was thus labelled as somatic type malignancy in a GCT. It is extremely important to aptly identify this component as treatment options and prognosis change significantly.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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Department of Histopathology, Jaslok Hospital and Research Centre, 15, Dr. G. Deshmukh Marg, Mumbai - 400 026, Maharashtra
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]