Primary neuroendocrine carcinoma of the thymus
A 47 years old male presented with chest pain and gradually progressing dyspnoea (MRC Grade III) of three months duration. He was a labourer and a non smoker with no history of exposure to any occupational or inorganic dusts. The chest pain was dull aching and mainly localized in left axillary region with no radiation and not related to the meals. He was also having cough with mucoid expectoration. There was no hemoptysis. Examination revealed averagely built person with BMI of 20, and no clubbing and lymphadenopathy. Respiratory system examination revealed diminished movements and breath sounds on the left hemithorax. Chest radiograph revealed a uniform density homogenous opacity in the lower left hemithorax with obliteration of the left cardiac border. The mediastinum was shifted to the right side []. CT scan of the thorax revealed a large well defined heterogenous density anterior mediastinal mass. There were some areas of necrosis within the mass. The mass was extending up to the pleural surface, but there was no infiltration of chest wall. There was no involvement of the mediastinal lymph nodes [ and ]. Abdominal ultrasonography did not revealed any organomegaly. Routine blood investigations were within normal limits. Serum cortisol levels were within normal levels. Fibreoptic bronchoscopy did not revealed any abnormality. Bronchial washings, bronchial brush biopsy and transbronchial needle aspiration biopsy of the mass were inconclusive. Trans-thoracic tru-cut biopsy of the mass revealed small round tumor cells, but the exact histological diagnosis remained uncertain. As the diagnosis was inconclusive, the patient was taken up for thoracotomy with excision of the tumor. Intra-operatively it was observed that there was a large firm mass in the mediastinum on the left side with invasion of the great vessels. The mass was extending up to the chest wall. Hence, debulking of the tumor was done to the extent possible. Complete excision of the tumor could not be done as it was infiltrating the great vessels and the pericardium. On gross examination, the tumor was uncapsulated, firm, pink-gray mass that was gritty on cut section. Internally there were few areas of necrosis. Histologically, the specimen revealed sheets of pleomorphic spindle shaped cells, with strikingly organoid growth pattern, with insulae, ribbons, festoons, and trabeculae of tumor cells []. In many areas, cellular nests became detached from surrounding fibrovascular septa and foci of central geographic necrosis were present. Immuno-histochemistry of the specimen proved the diagnosis of neuroendocrine carcinoma of the thymus with tumor cells expressing cytokeratin positivity, strong synaptophysin positivity, chromogranin A positivity and TTF-1 positivity [Figures –]. Post-operatively, he received radiotherapy with 4000 rads followed by chemotherapy consisting of Cisplatinum, Bleomycin and Doxorubicin every three weeks for four cycles. But the patient continued to be symptomatic, and his condition worsened over a period of next three months and he died subsequently five months after the diagnosis due to the distant metastasis and recurrence of the disease.