Abstract
Background. Somatic type malignancy (STM) occurs in 2% of all germ cell tumours (GCTs). The prognosis is unfavourable and the origin is poorly understood. Pathogenetic hypotheses involve direct transformation of teratoma, origin from totipotent cancer cells, or derivation from yolk sac tumour elements. Case Presentation. A 31-year-old patient was cured from testicular seminoma clinical stage IIc by orchiectomy and cisplatin-based chemotherapy. Nine years later, he experienced a late relapse with a mass sized 5 × 6 cm located at the former metastatic site. As no remission occurred after chemotherapy with three cycles of cisplatin, ifosfamide and etoposide, the mass was surgically resected. Histologically, the specimen consisted of neurofibroma with areas of malignant peripheral nerve sheath tumour and spots with mature bone formation. FISH analysis disclosed isochromosome 12p in the majority of evaluated cells suggesting somatic type malignancy (STM) of GCT. The patient is well 1 year after surgery. Conclusion. The pathogenesis of this STM remains enigmatic. The origin from GCT was evidenced by documentation of isochromosome 12p. Unrecognized teratomatous elements in the primary and totipotent cancer cells surviving the first chemotherapy could be hypothesized to represent the origin. STM developing from seminoma cells would be another novel hypothesis.
Highlights
Somatic type malignancy (STM) occurs in 2% of all germ cell tumours (GCTs)
A 31-year-old patient was cured from testicular seminoma clinical stage IIc by orchiectomy and cisplatin-based chemotherapy
somatic type malignancy (STM) encompass a wide spectrum of histologic appearances [4] with sarcoma of all subtypes comprising 50% and carcinomas of various subtypes comprising about 20% of cases followed by primitive neuroectodermal tumours (PNET) ranking third with 10% [5, 6]
Summary
Germ cell tumours (GCTs) have the potential to differentiate into many directions [1, 2]. Friedman and Moore were the first to document cases with “neuroepithelioma” and sarcoma arising within teratomatous germ cell tumours [3]. STMs encompass a wide spectrum of histologic appearances [4] with sarcoma of all subtypes comprising 50% and carcinomas of various subtypes comprising about 20% of cases followed by primitive neuroectodermal tumours (PNET) ranking third with 10% [5, 6]. STMs appear like typical primary neoplasms with no obvious histological resemblance to germ cell tumours. STMs are rare events that are encountered in about 3% of metastasized cases with GCT [5, 9, 10]. A patient with STM that is exceptional because of its clinical and histologic features
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