C. pulse granuloma

Foreign material typically elicits granulomatous reactions that include histiocytes and multinucleated giant cells. Pulse granulomas are peculiar reactions to vegetable matter characterized by clusters of hyaline rings admixed with inflammation and often with multinucleated giant cells or demonstrable vegetable matter. Pulse granulomas usually occupy the oral region. Extraoral pulse granulomas are currently believed to be extremely rare. The hyaline rings are believed to be related to cellulose or collagen, rather then vasculitis, based on cytochemical, morphometric, and ultrastructural studies. Pulse granulomas usually occur in the orofacial region. Extraoral pulse granulomas are currently thought to be rare. Pulse granulomas are important for 6 reasons: (1) Large pulse granulomas, which can be 3 centimeters in greatest diameter, can mimic neoplasia or infection clinically. (2) Pulse granulomas may be easily misdiagnosed as hyaline vasculopathy of hypertension, diabetes or amyloidosis because awareness of these entities is much greater than awareness of pulse granulomas, because hyaline rings of pulse granulomas morphologically resemble hyaline vasculopathy, because hyaline rings of pulse granulomas polarize light and are birefringent, and because demonstrable vegetable matter may be absent or inconspicuous. (3) Extraoral pulse granulomas are usually surrogate markers of serious pathology, which enables vegetable matter to escape the lumen of the alimentary canal. (4) Pulse granulomas in periprostatic soft tissue are harmless iatrogenic artifacts related to prostatic core biopsies. (5) Pulse granulomas may mimic granulomas of sarcoidosis. (6) Pulse granulomas in lymph nodes, mesocolonic fat, or soft tissue might help differentiate Crohn disease from ulcerative colitis.

Karamurzin YS, Narula S, Khanifar E, Kim YS, Wu ML. Pulse granulomas in highly unusual sites. Histopathology 2009;54:258-259.