Microsporum canis, a frequently encountered zoophilic dermatophyte associated with tinea capitis and tinea corporis, is rarely associated with a mycetoma-like presentation, grain formation, or systemic infection. The medical literature describes only six cases of M. canis causing mycetoma-like formations in immunocompromised and immunocompetent patients. This case report describes an unusual presentation of a common dermatophyte infection, and the literature review summarizes the importance of recognizing atypical presentations of dermatophyte infections. Such infections may warrant more aggressive treatment in immunocompromised patients.

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Angiosarcomas are rare malignant tumors of endothelial origin that occur predominantly in the adult population. To date, only 12 cases have been described after renal transplantation. We review the literature and present an additional case of a 59-year-old patient in whom lower-extremity lesions of cutaneous angiosarcoma developed several years after transplantation. Of the 13 patients, clinical details were available in only 12 cases. There were 10 male and 2 female patients. The mean age at diagnosis was 47.6 years (age range, 28-71 years). Almost all patients were on a combination immunosuppressive regimen, and the interval between transplantation and the development of the tumor was variable in the range of 8 months to 12 years. In five patients, the tumor arose within or adjacent to an arteriovenous fistula site. Cutaneous involvement was observed in only four cases. The histologic spectrum consisted of both well-differentiated and poorly differentiated tumors. In one patient, features of the hemophagocytic syndrome were clinically present and the tumor morphologically displayed prominent erythrophagocytosis. In two of the cases, including the patient described in the current report, polymerase chain reaction was performed on lesional tissue for human herpesvirus-8 and the result was negative for the presence of viral DNA. Despite the use of multimodal aggressive therapy in most patients, death as a result of disease dissemination occurred over variable time periods (range, 1-15 months).

Dimorphic fungal infections (histoplasmosis, blastomycosis, coccidioidomycosis, and cryptococcosis) can occur in immunocompromised and healthy individuals. Cutaneous involvement is often secondary and may be the presenting sign of systemic disease. These ominous infections are frequently clinically indistinct, and patient prognosis is influenced by a timely diagnosis and treatment. Morphologic differentiation between these organisms is not definitive, and tissue cultures represent the diagnostic gold standard in current day practice. However, tissue cultures are rarely obtained and merely represent an afterthought in seemingly unsuspecting cases. Furthermore, when performed, they may take several days or weeks for completion. In situ hybridization (ISH) utilizing oligonucleotide probes directed against fungal ribosomal RNA is a rapid and accurate assay for the identification of dimorphic fungi in paraffin-embedded tissue sections. We present five patients in whom ISH both prospectively and retrospectively confirmed the presence of a cutaneous infection (histoplasmosis, blastomycosis, coccidioidomycosis, and cryptococcosis). In all of the skin sections analyzed, dimorphic fungi were morphologically apparent but not diagnostically discernible. In summary, ISH is a valuable tool in the prompt diagnosis of cutaneous deep fungal infections.

A 62-year-old man presented with a 5-year history of symmetric, hard papules on both of his elbows. These lesions were completely asymptomatic, but they were of cosmetic concern to the patient. Summer and trauma reportedly exacerbated the appearance of new papules, which tended to evolve spontaneously, harden, and subsequently ulcerate. The patient's main medical problem was a long-standing history of rheumatoid arthritis treated with low-dose oral prednisone. Physical examination revealed multiple scattered papules bilaterally on the extensor surfaces of the forearms. These were 2-10 mm in size, red to violaceous, and hard. Some of the lesions had ulcerated centers or slight umbilication (Fig. 1A,B). Histologic examination revealed several granulomas in the mid- to deep dermis with central basophilic fibrillar collagen necrosis (Fig. 2A). The necrotic areas were interspersed with bands of neutrophils, lymphocytes, and leukocytoclastic debris. The periphery of these basophilic granulomas was lined by palisading histiocytes (Fig. 2B).