CHEST Guidelines-A-72-Year-Old-Woman-With-Previous-Pulmonary-Metast

A-72-Year-Old-Woman-With-Previous-Pulmonary-Metast

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The document presents a case study involving a 72-year-old woman with a previous history of pulmonary metastasis stemming from colic adenocarcinoma, who developed a new subpleural nodule in the right lower lobe of her lung. Initially, this nodule was suspected to be a neoplastic lesion due to her prior cancer history. A CT scan revealed the nodule had low central attenuation and no contrast enhancement, and a PET-CT scan showed no pathological uptake. Blood tests and markers indicated no infectious or malignant activity.<br /><br />The patient underwent a wedge resection of the nodule via video-assisted thoracoscopic surgery. The nodule exhibited features of central coagulative necrosis and a granulomatous reaction with various immune cells, a pattern not typical for malignancies. Special stains revealed the structure of the nematode Dirofilaria. The final diagnosis was pulmonary dirofilariasis, a condition caused by parasites of the genus Dirofilaria transmitted by mosquito bites, with the patient likely infected due to her environmental and occupational exposure.<br /><br />Dirofilariasis is primarily a zoonotic infection, rare in humans, and more frequent in animals. In humans, the larvae die in the tissues, forming nodules like the one observed in this patient. Diagnosis of pulmonary dirofilariasis can be challenging and is often mistaken for malignant lesions. Standard diagnostics, such as serological tests and radiology, are non-specific, necessitating histological examination of excised nodules for conclusive diagnosis. The patient required no further treatment post-excision, and the case underscores the importance of considering dirofilariasis in the differential diagnosis for solitary pulmonary nodules, especially in endemic areas.

Keywords

pulmonary dirofilariasis

subpleural nodule

Dirofilaria

granulomatous reaction

video-assisted thoracoscopic surgery

wedge resection

zoonotic infection

differential diagnosis

histological examination

solitary pulmonary nodules