Messy granuloma: an additional pattern of granulomatous reaction.

AIM There are six main types of granulomas in dermatopathology. The aim is to present and describe a seventh pattern of granuloma that we came across while studying biopsies of cutaneous leishmaniasis. MATERIALS AND METHODS We investigated 17 cases of cutaneous leishmaniasis. A granulomatous response was identified in 14 of them. The features that were common to all of them were noted. These common features were compared with the morphological characteristics of the already known six types of granuloma in 155 cutaneous biopsies from our archives. We also looked for figures of granulomas in cases of cutaneous leishmaniasis from the literature. RESULTS The granulomas identified in all of our cases of leishmaniasis were composed of epithelioid elongated glassy histiocytes, arranged in a randomly disorganized pattern. We dubbed these "messy" granulomas. Additionally, the granulomas presented with necrotic eosinophilic material that did not collect in the center, but rather intermingled with the elongated histiocytes. We found many examples in the literature in which the granulomas could be reclassified as messy. CONCLUSIONS Messy granuloma - although not pathognomonic of leishmaniasis - seems to be quite characteristic of leishmaniasis, at least of cutaneous leishmaniasis.