Pseudomycetoma caused by Microsporum canis in an immunosuppressed patient: a case report and review of the literature.

BACKGROUND: A 65-year-old woman with a history of liver and kidney transplantation presented with a pruritic and tender rash of 2-year duration on her left knee. METHODS: The patient had a physical examination, and multiple skin biopsies were performed. RESULTS: Examination showed a cluster of dome-shaped, violaceous papules. A skin biopsy specimen showed multiple granules containing basophilic material within the superficial to mid dermis. The grains were embedded in an eosinophilic substance and surrounded by granulomatous inflammation. A Gomori methenamine silver stain showed abundant septate hyphae, and cultures grew colonies of Microsporum canis. A diagnosis of dermatophytic granuloma, or pseudomycetoma, was made. After considering the patient's immune status, a prolonged course of fluconazole was initiated. CONCLUSION: 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.

Indolent systemic mastocytosis as the cause of a long history of unexplained hypotensive episodes.

Assessment of patients with unexplained hypotensive episodes in outpatient practice is often challenging, with an extensive differential diagnosis. The prevalence of systemic mast cell disease (MCD) is unknown, and the diagnosis is often elusive because serum and urine markers may become positive only after one of the self-limited, recurrent hypotensive episodes. Nevertheless, MCD is increasingly recognized as a cause of unexplained hypotension, secondary osteoporosis, and anaphylactic reactions to Hymenoptera stings. We describe a 38-year-old man who had a 15-year history of undiagnosed, recurrent hypotensive episodes with stereotypic symptoms. Extensive evaluation during these years was unrevealing. On physical examination, he appeared to be a healthy man with a prominent macular rash. Results of skin biopsy showed tryptase-positive mast cells. He had markedly elevated serum tryptase levels, and results of bone marrow biopsy revealed 10% mast cells; all these findings were consistent with indolent systemic mastocytosis. Key features in his history and physical examination prompted the conclusive testing. The most telling features were hypotension, tachycardia, and the rash (urticaria pigmentosa).

In situ hybridization in cutaneous deep fungal infections: a valuable diagnostic adjunct to fungal morphology and tissue cultures.

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.

Angiosarcoma in a chronically immunosuppressed renal transplant recipient: report of a case and review of the literature.

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).

Cutaneous palisaded allergic granuloma associated with rheumatic disease.

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).