Contributed by Hae-Sun La, MD and Tanner Bartholow, MDFINAL DIAGNOSIS
Granulomatosis with polyangiitis
DISCUSSION
Granulomatosis with polyangiitis (GPA) is a systemic inflammatory disease that is characterized by vasculitis as a major component of the disease process. The classic triad of sites involved by GPA are upper and lower respiratory tracts and the kidneys.
In this case, the patient presented with a saddle deformity of the nose, multiple cavitary lesions in the lungs, which showed geographic necrosis under microscopy, with kidneys involved by vasculitis. The serum was also positive for cytoplasmic antineutrophilic cytoplasmic antibody (c-ANCA).
The necrotizing lesions of GPA are not well-formed granulomas but have peripheral zone of palisaded histiocytes.
The etiology of GPA is unknown. GPA can occur at any age with an average of 50 years. The head and neck region, lung, and kidney are the most commonly affected sites.
Patients with GPA often have nonspecific abnormalities in laboratory studies including elevated white blood cell count, increased number of platelets, elevated erythrocyte sedimentation rate, and normochromic normocytic anemia. c-ANCA is associated with and is specific for GPA. Patients with complete remission can still have positive c-ANCA. However, the presence/absence of positive serum ANCA is not enough to rule in/out the diagnosis of GPA.
Major histologic manifestations of GPA include vasculitis (arteritis, venulitis, capillaritis), parenchymal necrosis (microabscesses and geographic necrosis), and granulomatous inflammation (microabscesses surrounded by granulomatous inflammation, palisading histocytes, scattered giant cells, etc.). For vasculitis, small arteries and veins are usually affected. Inflammation involved in GPA consists of mixed inflammatory cells including neutrophils, lymphocytes, plasma cells, eosinophils, histiocytes, and giant cells.
The diagnosis of GPA requires correlation of the histopathological findings with the clinical and serologic findings.
Without treatment, GPA is fatal. However, treatment with cyclophosphamide and prednisone is highly effective. Trimethoprim-sulfamethoxazole and methotrexate in addition to pulse cyclophosphamide are also used.
Contributed by Hae-Sun La, MD and Tanner Bartholow, MD
  |
