Abstract Introduction Primary mediastinal seminoma is a rare malignant germ cell tumor, accounting for 1-4% of mediastinal mass. A 30-year-old male presented with dyspnea, cough and orthopnea. Radiologic imaging showed a large anterior mediastinal mass with gross pericardial and left sided pleural effusions. We describe a case where the initial clinical findings suggested lymphoma, but final histopathology and immunohistochemistry (IHC) revealed seminoma. This report is unique due to diagnostic overlapping and scarcity of Indian information, which significantly altered the patient’s outlook. diagnostic overlapping and scarcity of Indian information, which significantly altered the patient’s outlook. Case Description A 30-year-old farmer presented with a 6-week history of breathlessness, cough, and orthopnea. He had no addictions or comorbidities, and on examination, pallor, icterus, dilated neck veins, and supraclavicular fullness were noted. Initial radiological evaluation revealed a 16 × 16.6 × 9.5 cm anterior mediastinal mass compressing the esophagus and trachea with findings of gross malignant pericardial and left-sided pleural effusions. He underwent a pericardial pigtail drainage, which was positive for malignancy on cytology, and lymphoma was initially considered. A frozen section from a USG-guided biopsy was consistent with a germ cell tumor. Further laboratory evaluation showed elevated levels of β-hCG; findings suggested a mediastinal non-seminomatous germ cell tumor. Prephase therapy with etoposide and cisplatin was completed. The patient was hemodynamically stable, following which he was discharged. On follow-up, the patient presented with a persistent cough, and further radiological investigations showed a 12.8 × 11.1 × 18.2 cm mediastinal mass pushing the Superior Vena Cava, pulmonary trunk, aortic arch, and trachea and infiltrating the pericardium. Cytology following core biopsy revealed a high-grade poorly differentiated malignant tumor characterized by a solid pattern of islands and lobules with intervening fibrous septa. IHC showed SALL4, OCT3/4, and D240 positive markers with AE1/AE3 paranuclear staining. Scrotal ultrasound revealed no testicular mass and minimal microlithiasis, confirming the diagnosis of primary mediastinal seminoma. Chemotherapy with etoposide, ifosfamide, and cisplatin was initiated along with appropriate supportive care and close monitoring Discussion The diagnostic intricacy of mediastinal germ cell tumors is illustrated by this case. Such shifts are not uncommon and emphasize the importance of carefully interpreting preliminary results. Crucially, the difference has predictive significance: seminomas, despite being uncommon in this area, react well to platinum-based chemotherapy. The case also emphasizes how urgent it is to stabilize oncologic emergencies like superior vena cava obstruction and malignant pericardial effusion. This abstract is funded by: None
Sachani et al. (Fri,) studied this question.