Detection of Polyomavirus in Merkel cell carcinoma by immunohistochemistry: report of three cases.

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin, arising from pluripotent precursors of Merkel cells. The tumor most frequently affects head and neck of elderly patients. It increases with sun exposure and after immunosuppression and organ transplantation. Because of a possible viral association, interest in MCC has escalated. A new polyomavirus, Merkel cell polyomavirus (MCPyV), was identified and associated to MCC. In support of this hypothesis, we report three new clinical cases of MCC in which we detected MCPyV by immunohistochemistry and provide an update on current thinking about the MCC.

Panniculitis with vasculitis.

Panniculitides encompass a great number of different entities; however, once a vasculitis has been detected histopathologically within the subcutaneous tissue, the differential diagnosis is mainly restricted to polyarteritis (panarteritis) nodosa (PAN), nodular vasculitis (NV), and Bazin's erythema induratum (EI). Patients with PAN may have the disease confined to the skin, but must be followed over a long period because many of them develop late systemic disease. The NV/EI group represents by far the most common type of lobular panniculitis with vasculitis; we prefer keeping the distinction between the two entities by underlining the equation NV positive tuberculin skin test = EI. Other lobular panniculitides with vasculitis are exceedingly rare and set in a systemic background which can be infectious (lepromatous leprosy panniculitides) or autoimmune/dysreactive (neutrophilic lobular panniculitis in rheumatoid arthritis, lobular panniculitis in inflammatory bowel disease).

Latency time in cutaneous leishmaniasis.

Latency period in cutaneous leishmaniasis was very rarely studied so far. We describe three patients, aged 71, 50 and 32 years, respectively, who contracted cutaneous leishmaniasis in Sicily. In all patients, clinical diagnosis was confirmed by histopathological examination and polymerase chain reaction: the latter was positive for Leishmania infantum in two patients and Leishmania canis in one. All cases were characterized by a very long period of latency, ranging from 11 to 16 months. These cases suggest that latency time of cutaneous leishmaniasis acquired in Sicily may be sometimes very long. The reasons of this latency time are unknown: latency depends neither by the involved species of sandflies and Leishmania nor by the immunological response of the patients: all laboratory tests, including immunological ones, were normal.

Erysipeloid: a review.

Erysipeloid is an occupational infection of the skin caused by traumatic penetration of Erysipelothrix rhusiopathiae. The disease is characterized clinically by an erythematous oedema, with well-defined and raised borders, usually localized to the back of one hand and/or fingers. Vesicular, bullous and erosive lesions may also be present. The lesion may be asymptomatic or accompanied by mild pruritus, pain and fever. In addition to cutaneous infection, E. rhusiopathiae can cause endocarditis, which may be acute or subacute. Endocarditis is rare and has a male predilection. It usually occurs in previously damaged valves, predominantly the aortic valve. Endocarditis does not occur in patients with valvular prostheses and is not associated with intravenous drug misuse. Diagnosis of localized erysipeloid is based on the patient's history (occupation, previous traumatic contact with infected animals or their meat) and clinical picture (typical skin lesions, lack of severe systemic features, slight laboratory abnormalities and rapid remission after treatment with penicillin or cephalosporin).

Erysipeloid.

We report a case of erysipeloid in a 73-year-old woman. The disease was characterized clinically by erythematous and erosive lesions on three fingers of the left hand. Diagnosis was made based on the patient's occupation (housewife), history of previous traumatic contact with a scorpion fish, typical inflammatory lesions located on one hand, lack of severe systemic features, mild laboratory abnormalities and rapid remission after specific treatment.

Interobserver reproducibility of histological features in cutaneous malignant melanoma.

AIMS: To assess the interobserver reproducibility of certain histological features proposed for the diagnosis of melanoma. METHODS: In a series of melanomas, 13 histological parameters were analysed: dimension > 6 mm, asymmetry, poor circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, asymmetrical melanin, melanin in deep cells, cytological atypia, mitoses, dermal lymphocytic infiltrate, and necrosis. RESULTS: The agreement (reproducibility) between the nine observers was excellent (kappa > 0.75) for 10 of the 13 examined features (dimension > 6 mm, poor circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, asymmetrical melanin, melanin in deep cells, mitoses, and necrosis). The agreement for asymmetry was very close to excellence (kappa = 0.74), and that for cytological atypia (kappa = 0.65) and dermal lymphocytic infiltrate (kappa = 0.47) was slightly lower, but in the fair to good agreement range. The kappa values obtained by comparison with the majority diagnosis were generally high (> or = 0.85); the mean value of kappa was lower (0.70) for only one parameter (dermal lymphocytic infiltrate). CONCLUSIONS: The parameters investigated showed an overall good reproducibility.

Cutaneous larva migrans with folliculitis: a new clinical presentation of this infestation.

Two patients (a 35-year-old woman and a 33-year-old man, just returned from trips to Jamaica and Barbados, respectively) presented with cutaneous larva migrans with folliculitis, a rare and atypical clinical presentation of this infestation. Histopathological examination revealed a follicular and perifollicular infiltrate prevalently consisting of lymphocytes and neutrophils, with numerous eosinophils. Both patients were successfully treated with oral albendazole.

The usefulness of clonality for the detection of cases clinically and/or histopathologically not recognized as cutaneous T-cell lymphoma.

BACKGROUND: The determination of clonality has proven to be a useful adjunct to the diagnosis of cutaneous lymphocytic infiltrates. It is considered particularly helpful for the distinction of mycosis fungoides (MF) and inflammatory dermatoses. OBJECTIVES: To verify the sensitivity of the polymerase chain reaction (PCR)-heteroduplex analysis of T-cell receptor gamma-chain gene (TCRgamma) rearrangements in patients with MF and to establish whether a clinicopathological re-evaluation of lesions previously unclassified or considered to be non-neoplastic entities but found to be monoclonal allowed the recognition of additional cases of MF. METHODS: Included in the study were 116 patients, seen at our Institute from April 2002 to September 2003 and tested for TCRgamma rearrangements. Thirty-six patients were affected by clinically and histopathologically proven MF, while the remaining 80 cases had not been classified or had been classified as non-neoplastic entities. The sensitivity of the molecular analysis was determined on the basis of the results obtained in the 36 patients with MF. The 29 cases of the second series of patients found to be monoclonal were clinically and histopathologically re-evaluated. RESULTS: Clonal rearrangements were found in 87.5% of patients with plaque stage MF and in 20% of those with patch stage MF. The clinicopathological re-evaluation allowed us to reclassify 15 of 29 monoclonal cases of the second series of patients as MF. CONCLUSIONS: The study showed that the PCR-heteroduplex technique can determine a high percentage of monoclonality only in plaque stage MF. However, in spite of the low sensitivity of the method, several cases previously unrecognized could be reclassified as MF when their clinical and histopathological features were re-evaluated taking into account the clonality of the lymphocytic infiltrate.

Histological features used in the diagnosis of melanoma are frequently found in benign melanocytic naevi.

AIMS: The histological features used in the diagnosis of melanoma may be present in benign naevi, but quantitative data are not available. The aim of this study was to establish the real prevalence of such features in naevi. METHODS: Ten dermatopathologists, from nine Italian institutions, studied a series of naevi. Eleven histological parameters currently used in melanoma diagnosis were analysed: asymmetry, poor circumscription, predominance of single melanocytes, irregular confluent nests, suprabasal melanocytes, hair follicle involvement, absence of maturation, cytological atypia, dermal lymphocytic infiltrate, mitoses, and necrosis. RESULTS: Ninety one naevi were examined: 22 junctional, 59 compound, and 10 intradermal. None of the studied parameters was seen in 22 of the benign naevi studied. One or more investigated features were found in 69 naevi. Poor circumscription was found in 49 cases, single melanocytic predominating in 42, asymmetry in 41, irregular confluent nests in 16, cytological atypia in 14, suprabasal melanocytes in seven, and hair follicle involvement in seven; absence of maturation, mitoses and necrosis were not found. CONCLUSIONS: The histological features used for the histological diagnosis of melanoma are often present in benign melanocytic naevi. This suggests a critical, non-mechanical use of them in melanoma diagnosis.

Melanocytic nevi of the breast: a histologic case-control study.

BACKGROUND: Melanocytic nevi in the genital, acral, and flexural sites often display clinical and histologic features that may simulate melanoma. We verified whether this is the case also for nevi of the breast. METHODS: Eleven dermatopathologists, from nine Italian Institutions, collected the specimens of melanocytic lesions from the breast and other body sites, excluding the acral, genital, and flexural areas, as controls. Cases and controls were matched for sex and age. All nevi were observed 'blindly' and simultaneously by all participants. For each lesion, 10 histological parameters were analyzed: asymmetry, absence of lateral demarcation of melanocytes, lentiginous proliferation, nested and dyshesive pattern, intraepidermal melanocytes above the basal layer, involvement of the hair follicle, absence of maturation of dermal melanocytes, melanocytic atypia, fibroplasia of the papillary dermis, and lymphocytic dermal infiltrate. Each parameter was scored 2 when present and 1 when absent or not valuable. A total score was calculated for each lesion. Results were statistically analyzed by the chi-square test and the Mann-Whitney U-test. RESULTS: One hundred and one nevi came from the breast area and 97 from elsewhere. Breast nevi exhibited significantly more atypical features than nevi from other sites. In particular, breast nevi with intraepidermal melanocytes, melanocytic atypia, and dermal fibroplasia were significantly more numerous. We did not find any sexual difference. CONCLUSIONS: To avoid undue concerns, dermatopathologists should be aware that melanocytic nevi of the breast may show a high degree of atypical features.

Progressive histiocytosis: description of a case of slow-course non-Langerhans cell histiocytosis.

We describe the case of a 37-year-old male patient who in 1992 started developing a skin eruption characterized by dark red to red-yellow papulonodular lesions that showed no tendency to spontaneous resolution. Visceral organs were not involved and the lipid pattern was basically normal. Histological examination revealed an infiltrate in the mid and upper dermis mainly consisting of mononucleated and multinucleated histiocytes with an abundant eosinophilic cytoplasm and a ground glass appearance, admixed with numerous xanthomatized cells and Touton and foreign-body giant cells. Immunohistochemical studies showed positivity for CD68 and negativity for CD1a and S-100 protein, whereas at the electron microscopy level the only peculiar finding was the presence of many desmosome-like junctions. The authors believe this to be a borderline form between papular xanthoma and reticulohistiocytosis.

Clear cell papulosis (pagetoid papulosis) in a non-Asian patient.

Clear cell papulosis is a recently described disorder which is characterized by multiple flat, slightly elevated, hypopigmented papules, distributed mainly on the lower part of the trunk of healthy children. Histologically, the disease shows 'clear cells' with a pagetoid appearance spread among keratinocytes in basal and suprabasal layers of the epidermis. These cells stain for AE1, CEA and EMA, making a relationship to eccrine or apocrine elements likely. All cases reported until now describe Asian children. The first European child with clear cell papulosis is presented.