Eruptive purpuric papules on the arms; a case of chemotherapy-induced inflammation of actinic keratoses and review of the literature.

Chemotherapy-induced inflammation of actinic keratosis can present in patients with subclinical actinic keratoses that become erythematous and pruritic within weeks of initiating systemic chemotherapy. The reaction is limited to sun-exposed areas and, classically, histologic findings of parakeratosis and epidermal necrosis with keratinocyte nuclear pleomorphism are present. Exuberant reactions with extensive epidermal necrosis may lead to subepidermal vesiculation. We report a case of a 67-year-old man with a history of chronic hepatitis B virus infection and recently diagnosed squamous cell carcinoma of the lung who was noted to have progressive asymptomatic violaceous papules on the extensor forearms and distal upper arms while hospitalized for possible sepsis following initiation of chemotherapy. A dermatology consulatation was requested to rule out possible vasculitis. It is important to recognize chemotherapy-induced inflammation of actinic keratoses in predisposed patients; it may be managed successfully with topical corticosteroids and does not necessitate discontinuation of the offending chemotherapeutic agent.

Congenital extrarenal malignant rhabdoid tumor in an infant with distal 22q11.2 deletion syndrome: the importance of SMARCB1.

Extrarenal rhabdoid tumor is a rare malignancy of infants and children, typically presenting in the soft tissue of deep, axial locations. We describe a rare dermal presentation of congenital extrarenal rhabdoid tumor in the left paraspinal region of a 6-month-old girl with germline deletion of chromosome 22q11.21q11.23. This case demonstrates that like other rhabdoid tumors, the SMARCB1 gene is also responsible for cutaneous extrarenal rhabdoid tumor oncogenesis.

Assessment of copy number status of chromosomes 6 and 11 by FISH provides independent prognostic information in primary melanoma.

Melanoma incidence has been rising steadily for decades, whereas mortality rates have remained flat. This type of discordant pattern between incidence and mortality has been linked to diagnostic drift in cancers of the thyroid, breast, and prostate. Ancillary tests, such as fluorescent in situ hybridization (FISH), are now being used to help differentiate melanomas from melanocytic nevi. Multicolor FISH has been shown to distinguish between these 2 with 86.7% sensitivity and 95.4% specificity. To assess the ability of FISH to differentiate melanomas with metastatic or lethal potential from those with an indolent disease course, we performed FISH with probes targeting 6p25, centromere 6, 6q23, and 11q13 on 144 primary melanomas with a minimal tumor thickness of 2 mm and compared the development of metastatic disease and melanoma-specific mortality as well as relapse-free and disease-specific survival between FISH-positive and FISH-negative cases. Of the melanomas, 82% were positive by FISH according to previously defined criteria. The percentage was significantly higher (93%) in cases that developed systemic metastases (n=43) than in patients that did not (77%, n=101). FISH-positive primaries had a significantly increased risk of metastasis or melanoma-related death compared with FISH-negative cases odds ratio 4.11; confidence interval, 1.14-22.7 and odds ratio 7.0, confidence interval 1.03-300.4, respectively. FISH status remained an independent parameter when controlling for known prognostic factors. These data indicate that the group of melanomas diagnosed with routine histopathology that lack aberrations detected by FISH is enriched for melanomas with a more indolent disease course. This suggests that molecular techniques can assist in a more accurate identification of tumors with metastatic potential.

Features of plexiform fibrohistiocytic tumor in skin punch biopsies: a retrospective study of 6 cases.

Plexiform fibrohistiocytic tumor (PFHT) is a mesenchymal neoplasm of intermediate malignant potential, which typically presents as a dermal or subcutaneous nodule, and is therefore often sampled by skin punch biopsy where diagnostic features may be subtle or absent. We retrospectively analyzed a series of 6 cases of PFHT to highlight for dermatopathologists the features of PFHTs useful to distinguish it from the other entities in the differential diagnosis. On the basis of the proportion of spindled fibroblastic cells to histiocytoid nodules in the biopsy specimen, we divided PFHT into 3 histologic variants: cellular, fibrous, and mixed. The biopsies also were compared with the final resection specimens, in an attempt to determine which histologic features in the original biopsies were most helpful in establishing a diagnosis. Clinical follow-up and immunohistochemistry were performed on all cases. The cellular and mixed variants were a lesser diagnostic challenge inasmuch as the distinctive features were more easily identifiable in small punch biopsy specimens. The fibrous variant proved more difficult to diagnose. Features most helpful in the diagnosis of PFHT were biphasic appearance with small, cellular, histiocytoid aggregates and accompanying plump spindled cells in the deep dermis and subcutis. Negative staining for CD34, NK1/C3, factor XIIIa, and beta-catenin by immunohistochemistry proved useful in excluding some of its mimics.

Immunophenotypic correlation between skin biopsy and peripheral blood findings in mycosis fungoides.

In mycosis fungoides (MF) with blood involvement, T-cell immunophenotypes in skin and blood have not been compared. Our aim was to evaluate T-cell immunophenotypes in skin by immunohistochemical analysis and compare results with flow cytometric (FC) findings in blood. Of 20 patients with MF with blood involvement, the immunophenotype was discrepant in 11 (55%). Compared with FC findings in blood, immunohistochemical analysis of skin samples failed to detect partial deletion of CD2 (5/11 [45%]), CD3 (3/11 [27%]), and CD5 (3/11 [27%]) and overrepresented deletion of CD7 in 2 (18%) of 11 patients. In addition, CD8+ MF was missed by immunohistochemical analysis in 2 (18%) of 11 patients. Identical T-cell populations were demonstrated by T-cell gene polymerase chain reaction in skin and blood in 8 of the 11 patients who had a discrepant immunophenotype. Awareness of the limitations of immunohistochemical analysis of skin samples is of practical value for pathologists interpreting skin biopsies in MF patients. In addition, our findings suggest CD8+ MF to be more common than previously reported.

Regulation of the psoriatic chemokine CCL20 by E3 ligases Trim32 and Piasy in keratinocytes.

Psoriasis is an inflammatory skin disorder with aberrant regulation of keratinocytes and immunocytes. Although it is well known that uncontrolled keratinocyte proliferation is largely driven by proinflammatory cytokines from the immunocytes, the functional role of keratinocytes in the regulation of immunocytes is poorly understood. Recently, we found that tripartite motif-containing protein 32 (Trim32), an E3-ubiquitin ligase, is elevated in the epidermal lesions of human psoriasis. We previously showed that Trim32 binds to the protein inhibitor of activated STAT-Y (Piasy) and mediates its degradation through ubiquitination. Interestingly, the Piasy gene is localized in the PSORS6 susceptibility locus on chromosome 19p13, and Piasy negatively regulates the activities of several transcription factors, including NF-kappaB, STAT, and SMADs, that are implicated in the pathogenesis of psoriasis. In this study, we show that Trim32 activates, and Piasy inhibits, keratinocyte production of CC chemokine ligand 20 (CCL20), a psoriatic chemokine essential for recruitment of DCs and T helper (Th)17 cells to the skin. Further, Trim32/Piasy regulation of CCL20 is mediated through Piasy interaction with the RelA/p65 subunit of NF-kappaB. As CCL20 is activated by Th17 cytokines, the upregulation of CCL20 production by Trim32 provides a positive feedback loop of CCL20 and Th17 activation in the self-perpetuating cycle of psoriasis.

Disseminated dermal Trichophyton rubrum infection - an expression of dermatophyte dimorphism?

We present a case of disseminated dermal infection caused by Trichophyton rubrum (T. rubrum). This rare variant of dermatophytosis has an atypical clinical and histopathological presentation and occurs exclusively in immunosuppressed patients. The large, broad, pleomorphic hyphae with scattered budding arthrospores in this variant of T. rubrum infection are unusual and may represent expression of dermatophyte dimorphism previously described in vitro.

Verrucous porokeratosis of the gluteal cleft (porokeratosis ptychotropica): a rare disorder easily misdiagnosed.

Porokeratosis represents a heterogeneous group of disorders characterized clinically by a distinctive ridge-like border and histologically by cornoid lamellae. A verrucous variant of porokeratosis involving the gluteal cleft has been recently described. We present 5 new cases and review the current literature to highlight the clinical and histopathologic features of this disorder. Descriptive terms including hyperkeratotic porokeratosis, genitogluteal porokeratosis, porokeratoma, follicular porokeratosis, and porokeratosis ptychotropica have all been used to describe this verrucous variant of porokeratosis involving the gluteal cleft. To avoid further confusion, we propose a consolidation of terminologies and suggest verrucous porokeratosis be added to the commonly described variants of porokeratosis.

Widespread porokeratotic adnexal ostial nevus: clinical features and proposal of a new name unifying porokeratotic eccrine ostial and dermal duct nevus and porokeratotic eccrine and hair follicle nevus.

Porokeratotic eccrine ostial and dermal duct nevus and a similar condition, porokeratotic eccrine and hair follicle nevus, are rare disorders of keratinization with eccrine and hair follicle involvement. We describe the clinical features in 5 patients, all of whom had widespread skin involvement following the lines of Blaschko. Two patients presented with erosions in the newborn period as the initial manifestation of their disease; one had an associated structural anomaly, unilateral breast hypoplasia; and one adult had malignant transformation in the nevus with development of multifocal squamous cell carcinomas. Three patients had histologic involvement of both acrosyringia and acrotrichia. Based on the observation of overlapping histologic features, we propose the name "porokeratotic adnexal ostial nevus" to incorporate the previously described entities porokeratotic eccrine ostial and dermal duct nevus and porokeratotic eccrine and hair follicle nevus.

Sequelae of World War II: an outbreak of chronic cutaneous nontuberculous mycobacterial infection among Satowanese islanders.

BACKGROUND: After World War II, residents of Satowan (population, 650 persons), an outer island in the state of Chuuk, Federated States of Micronesia, noted a high prevalence of a chronic, progressive skin disease known locally as "spam." METHODS: Island residents who had chronic, progressive verrucous or keloidal plaques for >3 months were considered case patients. Tissue specimens were obtained for culture, histopathological analysis, mycobacterial polymerase chain reaction (PCR), and comparison with the hsp65 gene of Mycobacterium marinum. We performed a case-control study involving all cases and randomly selected control individuals from the community. RESULTS: A total of 39 case patients were identified, with a median age of 26.0 years (range, 8-82 years); 74.4% were male, and the mean duration of disease was 12.5 years. A total of 98 control individuals were enrolled. Results of all 19 mycobacterial tissue cultures were negative, and histopathological analysis of all 9 lesions showed suppurative granulomatous inflammation with negative results of mycobacterial and fungal stains. In 7 of 9 paraffin-embedded samples, nontuberculous mycobacterial DNA was detected by PCR, and 2 sequenced products had 95% and 87% identity to M. marinum. All case patients were taro farmers (odds ratio, undefined; P < .01), and among taro farmers, when the analysis was controlled for sex, contact with water-filled World War II-era bomb craters was associated with infection (odds ratio, 8.2; P < .01). CONCLUSIONS: "Spam disease" is a chronic, progressive skin disease of high prevalence on Satowan and is associated with taro farming and contact with World War II-era bomb craters. Histopathological and PCR data demonstrate a nontuberculous mycobacterial infection as the cause.

Mycobacterium marinum presenting as large verrucous plaques on the lower extremity of a South Pacific Islander.

Mycobacterium marinum is an environmental, nontuberculous mycobacteria found in fresh and salt water, causing disease in humans through traumatized skin. We describe a young, healthy South Pacific Islander with chronic, progressive large verrucous plaques on the left lower extremity, with cultures positive for M. marinum. This morphology, distribution, and disease course is likely representative of an atypical presentation of M. marinum infection in South Pacific Islanders.

Orf-induced immunobullous disease: A distinct autoimmune blistering disorder.

BACKGROUND: Many complications have been reported after orf infection, including lymphadenopathy, secondary bacterial infection, and erythema multiforme. Rare associations with papulovesicular eruptions, including a bullous pemphigoid-like eruption, have also been described. OBJECTIVES: Our purpose was to clinically, histologically, and immunologically characterize two cases of orf-induced blistering disease, and to determine whether this condition represented a novel disease entity distinct from known immunobullous diseases. METHODS: Two patients were clinically described and skin biopsy specimens were collected for routine histology, direct immunofluorescence studies, and polymerase chain reaction analysis to detect orf viral DNA. Patients' sera were assessed for autoantibodies by indirect immunofluorescence studies using normal-appearing human salt-split skin, by Western blot analysis using keratinocyte extracts, dermal extracts, and recombinant type VII collagen, and immunoprecipitation studies of extracts from biosynthetically radiolabeled human keratinocytes. RESULTS: Two distinctive cases of severe, diffuse blistering eruptions after orf infection are described. In one patient, orf virus DNA was detected in the inciting orf lesion, but not in blistered skin, ruling out disseminated orf infection as a cause of the blisters. In both cases, histology revealed subepidermal blisters with mixed inflammatory cell infiltrates containing neutrophils and eosinophils, direct immunofluorescence microscopy studies demonstrated IgG and C3 deposited at the dermoepidermal junctions of perilesional skin, and indirect immunofluorescence studies demonstrated circulating antibasement membrane IgG that bound the dermal side of salt-split skin. Extensive immunoblot and immunoprecipitation studies failed to reveal a consistent, identifiable autoantigen. LIMITATIONS: We describe only two cases. The autoantigen recognized by circulating autoantibodies was not identified. CONCLUSIONS: Orf-induced immunobullous disease is a unique disease entity that is clinically and immunologically distinct from bullous pemphigoid, epidermolysis bullosa acquisita, and other known immunobullous conditions.