Pathogenesis of Testicular Germ Cell Neoplasia: A Conceptual Approach

Cytodiagnostic Dilemma in a Lung Mass as the First Presentation of Testicular Mixed Germ Cell Tumor Metastasis

Testicular mixed germ cell tumors (TMGCTs) are rare malignant tumors comprising of two or more types of germ cell tumors. Their onset may be undetectable and the patient may first present with symptoms of metastasis. We hereby report a case of a young male who presented with respiratory discomfort and had no symptoms of primary testicular tumor. CT-guided FNAC lung revealed mainly necrotic, keratinous debris with a focus of chondromyxoid stroma. Differential diagnoses of components of teratoma, squamous cell carcinoma and inclusion cyst was considered. FNAC was reported out for the possible presence of teratoma components. Retrospectively, physical examination and subsequent USG revealed testicular tumor. The case led to a diagnostic dilemma as the patient presented with no prior history suggestive of metastasis from testicular mixed germ cell tumor. The aim of the current case report is to alert the pathologists and clinicians about this uncommon clinical presentation and diagnostic relevance of FNA. It highlights that FNA lung revealing keratinous material should always be searched for the possibility of teratoma component.

Pure primary renal yolk sac tumour in an adult: extremely rare clinical finding

We present a rare case of an extragonadal retroperitoneal yolk sac tumour in an adult male, who presented with severe abdominal pain to his local hospital. Imaging revealed a large retroperitoneal soft tissue mass with no evidence of metastases. Initial biopsy demonstrated poorly differentiated carcinoma, favoured to be renal cell carcinoma. The patient underwent surgical resection following re-presentation with severe abdominal pain and significant interval enlargement of the mass. Laparotomy revealed a renal tumour that had ruptured through the left mesocolon into the peritoneal cavity. Postoperative histopathological examination revealed a yolk sac tumour involving the kidney, perinephric fat, renal sinus fat, renal hilar lymph node and colonic mesentery. Immunohistochemical staining for alpha-fetoprotein and glypican 3 was positive in the tumour cells without evidence of other germ cell elements, confirming the diagnosis of a pure yolk sac tumour. To our knowledge, this is an extremely rare case of a primary pure yolk sac tumour arising from the kidney in an adult.

Report of testicular tumour in a toddler: management beyond the testis

Testicular tumours in prepubertal children tend to be pure yolk sac tumours detected in stage I and have good prognosis. We describe a case of a 2-year old male child with a mixed testicular tumour presenting with stage IIC disease and managed with retroperitoneal lymph node dissection for residual retroperitoneal disease post adjuvant chemotherapy.

Testicular Germ Cell Tumors: Classification, Pathologic Features, Imaging Findings, and Management

Testicular germ cell tumors (TGCTs) demonstrate a wide variety of histopathologic, genetic, pathogenetic, and immunocytochemical characteristics and various clinical-biologic profiles and prognoses. Most TGCTs arise from an intratubular precursor cell referred to as germ cell neoplasia in situ (GCNIS), which is an embryonic germ cell with the potential to differentiate into a plethora of embryonic and extraembryonic lineages. Advances in pathologic examination and genetics paved the way for the 2016 World Health Organization (WHO) classification system, which recognizes two pathogenetically distinct groups of TGCTs. Although postpubertal tumors originate from GCNIS, almost all prepubertal tumors belong to the non-GCNIS category. Molecular testing for chromosome 12p amplification helps to distinguish the two tumor categories. Imaging techniques such as US, CT, MRI, and fluorine 18 (¹⁸F)-fluorodeoxyglucose PET/CT are pivotal to the diagnosis and staging, evaluation of complications and treatment response, and long-term surveillance of TGCTs. In addition, select MRI findings may help to differentiate a seminoma from a nonseminomatous mixed TGCT. Accurate diagnosis of TGCTs has therapeutic and prognostic implications. Although seminomas show exquisite response to chemotherapy and radiation therapy, postpubertal teratomas are highly resistant to both. The 2016 WHO classification system introduced changes in the diagnosis and management of TGCTs, including the development of new treatment and follow-up guidelines. Radiologists play an essential role in the optimal treatment of patients with TGCTs. Online supplemental material is available for this article. ©RSNA, 2021.

Contemporary Trends in Presentation and Management of Spermatocytic Seminoma

OBJECTIVE

To characterize the presentation and management of spermatocytic seminoma (SS) compared to classic seminoma in adults utilizing a large cancer registry.

METHODS

Patients >18 years of age in the National Cancer Database from 2006 to 2016 who underwent orchiectomy for testicular tumors were identified. Demographics, oncologic characteristics, and treatment patterns were compared between patients with SS and classic seminoma.

RESULTS

Of 53,481 adults receiving orchiectomy, 29,208 were diagnosed with classic seminoma and 299 (1%) with SS. Compared to patients with classic seminoma, SS patients were older (57 vs 39 years) and more likely to be African-American (odds ratio (OR) 1.8) and insured by Medicare (OR 2.0; all P <.05). SS patients had larger tumors on presentation (3-6 cm: OR 1.8; >6 cm: OR 1.8), but were less likely to have ≥pT2 stage (OR 0.5), regional nodal involvement (Clinical Stage II: OR 0.3), or distant metastatic disease (Clinical Stage III: OR 0.1; all P <.01). For postorchiectomy management, 73.6% of SS patients underwent surveillance while 24.5% had active treatment (retroperitoneal lymph node dissection, chemotherapy, radiation, or a combination). When stratified by year, there was an increasing trend toward surveillance compared to active treatment.

CONCLUSION

SS is a rare germ cell tumor that typically presents as a larger tumor in older patients. Although these tumors are less likely to be characterized by advanced disease compared to classic seminoma, many patients have undergone aggressive postorchiectomy treatment in the past. Importantly, treatment trends have shifted toward surveillance in recent years with adjuvant therapy limited primarily to higher stage tumors.

Molecular and epigenetic pathogenesis of germ cell tumors

The development of germ cell tumors (GCTs) is a unique pathogenesis occurring at an early developmental stage during specification, migration or colonization of primordial germ cells (PGCs) in the genital ridge. Since driver mutations could not be identified so far, the involvement of the epigenetic machinery during the pathogenesis seems to play a crucial role. Currently, it is investigated whether epigenetic modifications occurring between the omnipotent two-cell stage and the pluripotent implanting PGCs might result in disturbances eventually leading to GCTs. Although progress in understanding epigenetic mechanisms during PGC development is ongoing, little is known about the complete picture of its involvement during GCT development and eventual classification into clinical subtypes. This review will shed light into the current knowledge of the complex epigenetic and molecular contribution during pathogenesis of GCTs by emphasizing on early developmental stages until arrival of late PGCs in the gonads. We questioned how misguided migrating and/or colonizing PGCs develop to either type I or type II GCTs. Additionally, we asked how pluripotency can be regulated during PGC development and which epigenetic changes contribute to GCT pathogenesis. We propose that SOX2 and SOX17 determine either embryonic stem cell-like (embryonal carcinoma) or PGC-like cell fate (seminoma). Finally, we suggest that factors secreted by the microenvironment, i.e. BMPs and BMP inhibiting molecules, dictate the fate decision of germ cell neoplasia in situ (into seminoma and embryonal carcinoma) and seminomas (into embryonal carcinoma or extraembryonic lineage), indicating an important role of the microenvironment on GCT plasticity.