18-FDG Uptake in Pulmonary Dirofilariasis

Abstract

Solitary pulmonary nodules are a common finding on chest radiography and CT. We present the case of an asymptomatic 59-year-old male found to have a 13 mm left upper lobe nodule on CT scan. The patient was asymptomatic and the CT was performed to follow up mediastinal and hilar lymphadenopathy that had been stable on several previous CT scans. He had a history of emphysema and reported a 15 pack-year smoking history. PET-CT was performed which demonstrated mild 18-FDG uptake within the nodule. Given his age and smoking history, malignancy was a consideration and he underwent a wedge resection. Pathological examination revealed a necrobiotic granulomatous nodule with a central thrombosed artery containing a parasitic worm with internal longitudinal ridges and abundant somatic muscle, consistent with pulmonary dirofilariasis. Dirofilaria immitis, commonly known as the canine heartworm, rarely affects humans. On occasion it can be transmitted to a human host by a mosquito bite. There are two major clinical syndromes in humans: pulmonary dirofilariasis and subcutaneous dirofilariasis. In the pulmonary form, the injected larvae die before becoming fully mature and become lodged in the pulmonary arteries.

Pulmonary coin lesion mimicking lung cancer reveals an unexpected finding: Dirofilaria immitis

“…Usually in the chest X ray a subpleural pulmonary nodule sized 1-3 cm with well-defined margins is diagnosed. The lesions are usually detected at the right lower lobe (1,8). However, the pulmonary nodules can be multiple or bilateral (3).…”

“…However, this examination showed no uptake of 18-fluorodeoxyglucose (18-FDG). Stone et al and Kang et al reported each of one case of HPD that both showed a mild uptake of 18-FDG (4,8). Other examination, such as angiography of the right side of the heart and pulmonary artery, transthoracic needle aspiration, examination of bronchial washings and biopsy or sputum cytology do not assist the diagnosis of the disease (1).…”

“…The definite diagnosis of the HPD is made through the wedge resection of the nodule (1,3,7,8). Macroscopically, the resected histological specimen consists of a spherical centrally necrotic nodule 1-3 cm in diameter that is surrounded by a granulomatous border and normal lung parenchyma.…”

Dirofilaria immitisin a child from the Russian Federation

“…In Western Europe, D. immitis is widespread causing severe cardiac signs in dogs [ 20 , 23 ]. In humans, pulmonary localizations of this parasite are observed [ 24 ], but the focal lesion in the lungs is often initially misdiagnosed as a tumor [ 23 ]. There are limited observations of other localizations of this parasite in humans, such as the chest, usually discovered in the course of coronary angiography [ 19 ], spermatic cord [ 17 ], scrotum [ 1 , 6 , 10 , 15 , 26 ], oral area [ 3 , 9 ], ovaries [ 16 ], liver [ 11 ], or subcutaneous tissue [ 4 , 7 ].…”

Infectious Alertness in Removal Benign Neoplasms in the Maxillofacial Area

“…Введение. Дирофиляриоз человека -паразитарное заболевание, трансмиссивный гельминтоз, вызванный паразитированием нематод рода Dirofilaria, чаще всего D. repens и D. immitis, которое протекает с преимущественным поражением кожи (63%), конъюнктивы (50%), слизистых оболочек, подкожной клетчатки, реже -внутренних органов, из которых наиболее часто поражаются легкие [1,2,3]. В организме человека самки Dirofilaria способны достигать половой зрелости, но не могут размножаться микрофилярии, поэтому человек не может являться распространителем данного заболевания [4,5].…”