Lupus vulgaris is a clinical variant of cutaneous tuberculosis, a rare subtype of extrapulmonary infection caused by the Mycobacterium tuberculosis complex. A paucibacillary form associated with high degrees of immunity, predominantly in the face, may present several clinical and histopathological differential diagnoses, which makes its diagnosis challenging. We present a case of lupus vulgaris in an immunocompetent patient, whose initial clinical presentation and histopathology did not suggest the condition. The objective is to highlight the relevance of the hypothesis of cutaneous tuberculosis as an important differential diagnosis, especially in endemic areas.

Paracoccidioidomycosis, the most prevalent deep mycosis in Latin America, is caused by dimorphic species of the genus Paracoccidioides, affects predominantly male rural workers between 30-50 years of age and is an important cause of morbidity and mortality. It can present in two clinical forms: acute/subacute or chronic. In rare cases paracoccidioidomycosis may simulate neoplasia and must be considered as a differential diagnosis of intra-abdominal tumors in endemic areas. We report an exuberant case of subacute paracoccidioidomycosis in an elderly lady, although it is more frequent in the juvenile form. Multiple facial skin lesions were associated with a wasting syndrome and extensive adenopathy including in the hepatic area, causing bile duct dilatation simulating a cholangiocarcinoma. Skin histopathology was diagnostic and antifungal treatment allowed complete resolution of cutaneous and systemic lesions, thus highlighting the merit of the dermatologist, who was fundamental for the conclusive diagnosis and institution of specific therapy, resulting in a favorable outcome.

Carcinoma cuniculatum is a rare variant of low-grade and well-differentiated squamous cell carcinoma. It is a locally invasive tumor, although it has low metastatic potential. It was originally described in the plantar region but may exceptionally appear in other locations. It predominates in middle-aged men and presents clinically as an exophytic, solitary, painful tumor, with insidious growth. Histologically, this tumor simulates a variety of benign dermatoses and may require several biopsies for the correct diagnosis. It is often misdiagnosed as a viral wart, due to the clinical similarity and the indolent course. The treatment of choice is surgical excision due to the high risk of recurrence and locally aggressive behavior. Amputation can be performed in cases of deep tissue invasion. We present a case of carcinoma cuniculatum in which the late diagnosis favored the invasion of the underlying bone, resulting in amputation of the affected finger.