Revisiting the Clinical and Histopathological Aspects of Patients with Chromoblastomycosis from the Brazilian Amazon Region

Background And Aims: Chromoblastomycosis is a chronic fungal infection caused by species of the family Dematiaceae. Fonsecaea pedrosoi is the most common etiological agent. The objective of this study was to describe the epidemiological and mycological profile of patients with chromoblastomycosis from the Amazon region of Brazil and to correlate the clinical forms with the histopathological findings and severity criteria.

Methods: Sixty-five patients were submitted to mycological (direct, culture, and microculture) and histopathological (hematoxylin-eosin staining) examination. Severity of the disease was classified according to the criteria proposed by Carrión in 1950.

Results: Most patients were males (93.8%) and laborers (89.2%). There was a predominance of verrucous lesions (55.4%), which were mainly found on the lower limbs (81.5%). Two major types of tissue reaction were observed: a granulomatous reaction characterized by the formation of suppurative granulomas rich in fungal cells, which were almost always seen in verrucous lesions, and a reaction characterized by the formation of tuberculoid granulomas with few parasites, which were mainly found in well-delimited erythematous plaque-like and cicatricial lesions (p = 0.0001). A peculiar type of organized mycotic granuloma was observed in 20 subjects. Suppurative granulomas were more frequently detected in severe lesions (p = 0.0189) and in lesions with a duration of >10 years (p = 0.0408).

Conclusions: These results suggest that verrucous lesions present a less competent inflammatory tissue response than patients who develop a well-formed tuberculoid reaction. The latter is associated with a more effective immune response as observed in the limited clinical forms of chromoblastomycosis.