Our case was a 33 years old male, a resident of Kathmandu, who was admitted two and a half years ago with fever on and off for one month, productive cough and shortness of breath. He was of average weight, was non-vegetarian, with history of consumption of crabs and snails over the last three years. He was found to have pleural effusion on ultrasound. Laboratory reports at the time showed leukocytosis, 15,400/cu mm with normal differential counts and a raised ESR of 25 mm in 1 hour. CRP was positive. The peripheral blood smear did not show any abnormal cells and liver function test and renal function test were also normal. Sputum test was negative for acid fast bacilli (AFB) or parasitic structures. Pleural fluid was tapped under image guidance and sent for biochemical, microbiological and cytological evaluation. It showed raised protein (6.4g/dL) and Lactate dehydrogenase (LDH) (1243IU/L). No organisms were found. The cell count was low but consisted predominantly of lymphocytes. Based on these finding, even though no definite proof of tuberculosis was found, patient was started on antitubercular treatment. Initially the patient showed improvement.
However, about one year later patient presented again to the hospital with cough, heaviness in chest and hemoptysis. HRCT chest showed a small irregular cavitary lesion measuring 18 x 14 x 15mm with small fluid level in the superior segment of lower lobe of left lung. The cavity was surrounded by ground glass density, multiple small nodules and linear streaks extending to the pleura in the medial aspect. No abnormal enhancement was seen on the contrast enhanced images (Fig. 1).
Overall impression was of pulmonary TB. His laboratory tests showed a normal complete blood count but raised ESR, 49mm in 1 hr. His lipid profile was deranged but otherwise, renal and liver function tests were normal. Patient also underwent bronchoscopy which did not reveal any additional abnormality. Sputum, bronchial brushing and bronchoalveolar lavage were also examined, all of which were negative for any organisms and for malignant cells. This time sputum examination by geneXpert, i.e. (Polymerase chain react) was also done which also did not reveal any tubercle bacilli. Mantoux test was positive with an induration of 21mm. Patient was sent home with antibiotics and reassurance and kept on follow up.
However, his symptoms got worse with increasing hemoptysis and fever and the patient was suspected to have aspergillosis in the cavitary lesion identified by HRCT and so he underwent a lobectomy. Gross examination of the lung showed a shiny pleura and spongy brown cut surface. A tiny cavitary lesion measuring 5 mm was identified. Representative sections were taken. Hematoxylin and eosin stained sections revealed a parasitic structure within the cavity with a thick cuticle and some serous glands within the body cavity. The cavity had denuded epithelium and was lined by palisading histiocytes. There was dense lymphohistocytic infiltration along with few eosinophils and many foreign body granulomas. Within these foreign body giant cells, multiple refractile oval to angulated ova were identified. These structures were positive on Periodic acid Schiff (PAS) stain (Fig. 2, Fig. 3).
The surrounding lung parenchyma showed mild edema. With these findings a diagnosis of paragonimiasis was made. Species identification was not possible. Serological tests were not available for confirmation.
CT Lung window showing a cavitating lesion, small nodules and linear streaks extending to the pleura.