Thymoma presenting as massive pleural effusion: An unusual presentation

Introduction

Incidence of thymic tumours is low i.e. 2.5-3.2/10,00,000 population.1 It usually occurs between 40 and 60 years, with equal gender predilection.2 Two-third to three quarter cases are benign in nature and do not show gross or microscopic invasion of surrounding structures. Thymoma usually presents as an anterior mediastinal mass. Pleural involvement is a very rare manifestation of thymoma. We are reporting a case of massive pleural effusion who was later diagnosed as a case of thymoma. Only few cases have been reported regarding the unusual presentation of thymoma as pleural effusion.

Case Report

A 55-year-old male, smoker, came to the hospital with the complaints of dry cough and shortness of breath for 1 month. It was associated with loss of appetite and weight loss for 1 month. There was no history of fever, joint pain, rash and any other systemic complaints. There was no history of anti-tubercular treatment in the past. There was no history suggestive of myasthenia gravis and hypogammaglobulinemia. There was history of pleural fluid tapping from outside (haemorrhagic, exudative, with the presence of atypical cells).

With complain of difficulty in breathing, he presented to our institute. He had oxygen saturation 92% at room air, pulse rate 120/min, blood pressure 110/70mm Hg and respiratory rate 24/min. Respiratory System examination revealed chest movements decreased on right side, dull note on right side and air entry decreased on right side. Chest X- ray (Figure 1) done at presentation, was suggestive of massive pleural effusion on the right side.

Fiberoptic bronchoscopy was done, and bronchial wash was suggestive of atypical cells. Trans bronchial lung biopsy showed fragmented bronchial mucosa with alveoli without atypical cells. Thoracoscopy was done. On thoracoscopy, haemorrhagic pleural fluid was present on right side without nodules and minimal adhesions were present. Pleural biopsy was done by video thoracoscopy. Pleural biopsy was suggestive of fibro collagenous tissue with hyalinization and chronic inflammation. Inflammatory cells, some histiocytes with prominent nucleoli were also seen. Immunohistochemistry showed that Pan CK, vimentin, CK7, CK5/6, p63, calretinin were negative.

Figure 1

Chest x-ray suggestive of right sided pleural effusion.

Figure 2

Chest x-ray suggestive of mediastinal mass with minimal pleural effusion.

Haemorrhagic pleural fluid was drained. Patient’s symptoms improved. Radiologically effusion decreased. Figure 2 showed the Chest X-ray after the thoracoscopy, suggestive of mediastinal mass with right sided effusion. CECT Chest (Figure 3) was done. It showed large fairly well marginated heterogeneously enhancing anterior mediastinum mass in the retrosternal/prevascular region without vascular invasion. Mild right pleural effusion and pericardial effusion were also seen without any evidence of pericardial thickening or nodularity.

Figure 3

CECT Chest suggestive of large fairly well marginated heterogeneously enhancing anterior mediastinum mass in the retrosternal/prevascular region without vascular invasion

Figure 4

Tru cut biopsy of the mass showing tumour cells with round to oval shape with hyperchromatic nuclei (arrows marked)

Fine needle aspiration and tru cut biopsy of the anterior mediastinal mass were done under ultrasound guidance. Fine Needle Aspiration Cytology showed haemorrhagic background with clusters of atypical cells, nuclear atypia and anisonucleosis. Tru Cut Biopsy (Figure 4) showed tumour cells made up of loose sheets of round to oval cells with hyperchromatic nuclei and pale eosinophilic cytoplasm. Focal spindle cells were present with pale cytoplasm. Mitosis were up to 3/10HPF. Findings were suggestive of thymoma. Patient was referred to the oncologist for further management and he was reported to have died after 1 month.

Discussion

Thymoma usually presents as anterior mediastinal mass. Pleural involvement is a rare presentation of thymoma. Table 1 shows the review of literature of 5 case reports of thymoma presenting as pleural effusion including the present case. We are presenting another case report from India regarding such presentation of thymoma. Anirban Das et al5 reported the first case of thymoma presenting as pleural effusion

We reviewed the literature and found 4 cases of thymoma associated with pleural effusion. Out of 4 cases reported so far, none have presented as massive pleural effusion. As shown in Table 1, in all case reports including our case pure red cell aplasia, hypogammaglobulinemia and myasthenia gravis were absent. In two cases,3, 6 spontaneous regression of pleural effusion was reported. In one case, spontaneous regression of tumour was also reported.6 One possible cause of the spontaneous regression may be increased internal pressure, probably associated with rapid tumor growth, leading to massive necrosis with resulting chest pain, inflammatory reaction with pleural effusion and subsequent tumor regression. The serum CYFRA level may be a useful marker for the evaluation of the clinical course of thymoma with extensive necrosis. 6 Pleural thymoma is another entity that can mimic our case.7

Malignant thymoma carries poor prognosis and surgical resection remains the mainstay of treatment.8 In our case, patient of thymoma presented with massive pleural effusion. This case highlights that rarely thymoma can present as massive pleural effusion.

Conflicts of Interests

None declared.

Source of Funding

None.