Dirofilariasis



Dirofilariasis











Low-power view of a necrotic pulmonary nodule image shows that the nodule is well demarcated and destroys normal lung parenchyma. A little rim of normal lung parenchyma is still present image.






High-power view of a nonviable worm typical of dirofilariasis is present image. The worm is embedded in necrotic material, which makes it difficult to identify.


TERMINOLOGY


Definitions



  • Infectious condition caused by helminth


ETIOLOGY/PATHOGENESIS


Etiology



  • Caused by Dirofilaria immitis



    • Dirofilariasis is more common in dogs


    • Humans are accidental hosts


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Uncommon infectious condition


  • Age



    • Can occur at any age, and infection has been described in children and adults


    • More common in adults


  • Gender



    • May be more common in males than in females


  • Ethnicity



    • No ethnic predilection


Site



  • Worms lodge in the heart but die before reaching maturity


  • Worms pass into pulmonary arteries


  • Right lung appears to be more commonly involved


  • Peripheral lung lesions are by far more common


  • Central lung lesions are unusual


Presentation



  • Symptoms



    • Cough


    • Dyspnea


    • Wheezing


    • Chest pain


    • Fever



      • Some patients may be asymptomatic


Laboratory Tests



  • Eosinophilia may be present in about 10-15% of patients


Natural History



  • Not associated with immunosuppression


  • In some cases, it is associated with history of previous malignancy


Treatment



  • Surgical approaches



    • Complete surgical resection is curative


Prognosis



  • Excellent


IMAGE FINDINGS


General Features



  • May present as single or multiple lung nodules


MACROSCOPIC FEATURES


General Features



  • Well-circumscribed necrotic nodule of soft consistency ± hemorrhage

Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Dirofilariasis
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