BLACK GRAIN MINIMYCETOMA CAUSED BY PYRENOCHAETA-MACKINNONII - THE FIRST CLINICAL CASE OF EUMYCETOMA REPORTED IN BARINAS STATE, VENEZUELA - CLINICAL-HISTOLOGICAL FEATURES AND CASE TREATMENT

A 39-year-old male Venezuelan farmer from a low socio-economic and edu cational background and resident of the town of Pedraza, Barinas state (which is located in the southwestern region of Venezuela) came to th e city of Merida for a clinical evaluation of a small painless << tumo r-like >> lesion located on the dorsal area of the right toe. The pati ent indicated that the lesion first appeared about six months ago; the clinical examination revealed a << tumorlike >> swelling induration o f the dorsal region of the right toe, painless with a bluish-purple co loration of the skin having a hard consistency of about 2 x 2 cm in si ze. In his medical history, the patient reported that he had injured h is right foot when he accidentally stepped on a dry wood splinter, whi ch later caused the present lesion. He also mentioned that this lesion has shown a slow but steady growth. An extensive local surgical excis ion of the << tumor-like >> lesion was made under local anaesthesia. T he surgical procedure allowed for a complete removal of the cutaneous and sub-cutaneous tissues of the lesion. No bone or tendinous damage w as observed. The microscopic examination of the removed << tumor-like >> lesion showed and irregular oval shape of about 2 cm in size, the t issue sample had a greyish colour showing some scattered brownish-yell ow dotted coloured areas. The tissue sample was fixed, dehydrated and cut. The slide tissue sections obtained were stained by Hematoxylin-eo sine (H&E), Periodic acid of Schiff (PAS) and Gomori's methenamine sil ver nitrate techniques. The histological microscopic examination of th e H&E stained tissue sections revealed the presence of a purulent mult iple microabcess pattern of cellular reaction. Numerous polymorphonucl ear cells were observed around the granules of the fungus agent as wel l as some monocytic, lymphocytic, plasmocytic and macrophagic type cel ls were found peripherically to the microabscess cellular reaction. Th e observed granules of the fungus agent were lobulate and irregularly shaped with a brownish colour, the periphery of the granule has numero us hialine-cilindrical hyphae and small vesicle structures located mai nly in the peripherical (cortical) zone and less in the inner (medular ) zone of the granules of the present infection causal agent. Based on the clinical and histological observations we concluded that the pati ent had a minimycetoma lesion due to Pyrenochaeta mackinnonii. After t he surgical treatment of the lesion, a clinical therapeutical treatmen t with itraconazole 400 mg daily was recommended. The early diagnosis and appropriate treatment of the case indicates a good prognosis for t he patient.