Folliculocentric cutaneous presentation of disseminated Candida krusei infection in a patient with acute myeloid leukemia.

Candida krusei (C. krusei) is a multidrug-resistant opportunistic fungal pathogen that may cause disseminated infections in immunocompromised hosts. However, its clinical and histologic features are not well-characterized. We present a unique case to contribute to the growing knowledge base associated with this organism. During hospitalization for neutropenic fever, a 19-year-old man with acute myeloid leukemia, who underwent hematopoietic stem cell transplantation, developed a generalized folliculocentric eruption following initiation of antifungal therapy for newly diagnosed C. krusei fungemia. Despite adequate antifungal coverage and negative blood cultures, the follicular-based erythematous papules persisted. Biopsies demonstrated yeast within ruptured follicles, without angiotropism or involvement of the interfollicular dermis, subcutaneous tissue, or stratum corneum. Concurrent skin tissue cultures confirmed C. krusei. The patient remained febrile despite aggressive antifungal therapy, with relapse of leukemia and subsequent death. Our case is unusual given the development of cutaneous lesions following clearance of fungemia, with yeast limited to ruptured follicular lumina, possibly indicating a primary cutaneous source or early transfollicular/transepidermal elimination. Given the limited available descriptions of cutaneous histopathology for C. krusei, we seek to add to the understanding of its pathophysiology and aid in the diagnosis and treatment of this often fatal infection.

Pseudoepitheliomatous hyperplasia and transepidermal elimination in lepromatous leprosy: does T-cell plasticity play a role?

BACKGROUND: The longstanding concept of a Th1-Th2 dichotomy in leprosy, with Th1-predominant tuberculoid leprosy and Th2-predominant lepromatous leprosy (LL), has recently been challenged, and Cbl-b overexpression may emerge as an important factor in anergy and progression of LL. Moreover, Th17 and Th22 subsets have been identified as Th1-Th2 modulators in inflammatory skin diseases, most notably psoriasis, but their roles in leprosy have not yet been elucidated. The occurrence of pseudoepitheliomatous hyperplasia (PEH) with transepidermal elimination of mycobacteria in LL patients, which could theoretically be a portal for contact transmission, thus raises important immunological questions: Do Th17 and/or Th22 subsets mediate epidermal proliferation akin to Th1-driven psoriasis in supposedly Th2-predominant LL disease, and is the Th1-Th2 immunostat set systemically or locally? Furthermore, which microRNAs (miRs), signal transducers, and activators of transcription (STAT) proteins regulate this transition in leprosy, if any, and does differential Cb1-b expression play a role? OBSERVATION: A 71-year-old man presented with an infiltrative dermopathy characteristic of LL, as well as several hyperkeratotic plaques. Microscopic examination of the hyperkeratotic lesions demonstrated PEH with loss of the grenz zone and transepidermal elimination of acid-fast bacilli, whereas classic histopathologic features of LL were present at other sites. HYPOTHESES: We hypothesize that: Th17 and Th22 T-cell subsets act locally to induce T-cell plasticity in LL lesions, manifesting PEH; miR-181a is normal or increased in LL lesions with PEH compared to its expressional loss in classic LL lesions; miR-21 and STAT3 are increased in LL lesions with PEH, given their association with epithelial hyperproliferation; and Cbl-b is diminished in LL lesions with PEH compared to classic LL lesions. CONCLUSION: By understanding the factors that regulate T-cell and cytokine responses in leprosy, it should be possible to recognize these dynamic immunologic processes clinically and histopathologically and devise specific immunologic interventions.

Specific detection of trichodysplasia spinulosa­associated polyomavirus DNA in skin and renal allograft tissues in a patient with trichodysplasia spinulosa.

BACKGROUND: Trichodysplasia spinulosa (TS) is a rare, disfiguring skin condition that affects immunosuppressed patients, universally involving the central face. New data point to the recently discovered TS-associated polyomavirus (TSPyV) as the causative agent. OBSERVATIONS: We report a case of TS in a 48-year-old African American man after renal transplant; via polymerase chain reaction and sequencing, confirm the detection of TSPyV in lesional skin; and report the novel detection of TSPyV DNA in renal allograft tissue. Results of polymerase chain reaction analysis were negative for Merkel cell polyomavirus in lesional skin. Fifteen months later, urine cytologic findings showed morphologic evidence of a urinary tract polyomavirus infection. Results of SV40 immunohistochemical analysis were negative in lesional skin, renal allograft, and urine specimens. CONCLUSIONS: To our knowledge, this is the first reported case in which TSPyV DNA has been detected in extracutaneous tissues and the third with combined ultrastructural and molecular confirmation of the presence of TSPyV in lesional skin. Lack of detection of other pathogenic human polyomaviruses in this patient's skin supports the specific role of this polyomavirus in the genesis of TS. Further basic science studies are needed to determine the exact pathomechanisms of this polyomavirus and to explore possible tumorigenic roles in other skin diseases.