Nematomas

Nematomas is a term that appears in some parasitology and veterinary texts to describe nodular lesions associated with nematode infection. It is not a universally standardized medical diagnosis and is used inconsistently; some authors prefer terms such as nematode granuloma or parasite-induced nodules. The concept generally refers to localized nodules that form in response to migrating, encysted, or degenerating nematodes within tissues.

Pathophysiology typically involves a localized immune response to nematodes or their remnants. This can produce granulomatous inflammation with eosinophil-rich infiltrates, fibrosis, and sometimes calcification. The nodules may form in subcutaneous tissue, muscle, or organ capsules, and they can arise from chronic inflammatory processes around living or dead parasites.

Clinically, nematomas present as solitary or multiple nodules that may be palpable, slowly enlarging, and occasionally tender. They can mimic neoplastic masses, making accurate diagnosis important. Patients may be asymptomatic or experience pressure effects depending on the lesion’s size and location.

Diagnosis relies on a combination of imaging, histopathology, and parasitological testing. Imaging modalities such as ultrasound, computed tomography, or magnetic resonance imaging can characterize nodules but often cannot identify the parasite. Biopsy or excision with histological examination may reveal granulomatous inflammation and nematode elements. Serology, stool testing, or molecular assays can help identify the underlying parasite when appropriate.

Treatment and prognosis depend on the causative parasite and lesion accessibility. Anthelmintic therapy is used for systemic infections, while surgical excision may be indicated for localized nodules or diagnostic uncertainty. Overall prognosis is favorable when the underlying infection is treated and the nodules are managed appropriately.

See also: nematodes, granuloma, parasitic infections.