Solitary and multiple epidermolytic acanthoma: A demographic and clinical study of 131 cases.

BACKGROUND: Epidermolytic acanthoma (EA) is a rare, benign acquired cutaneous keratosis displaying epidermolytic hyperkeratosis in more than 50% of its surface. Because of the sparsity of comprehensive studies, little is known on the patient demographics and clinical characteristics of this uncommon entity. We wish to comprehensively characterize the clinical and demographic features of EA and to differentiate it from its mimickers. METHODS: We carried out a retrospective review of 131 cases of EA, recorded clinical and histopathologic features and performed linear regression of yearly incidence rates to assess for possible under-reporting of this entity. RESULTS: EA affected both genders equally. We found 9.08 cases per 100 000 biopsy specimens per year and linear regression analysis showed significantly decreasing incidence rates. Analysis of the anatomical site distribution of EA lesions showed a more frequent genital location in men (39.1% of cases in men, as compared to 11.3% for women). Contrary to previous studies, lesions were most frequently single (91.7%) and the mean age of presentation was 57.8 years. CONCLUSION: The presented largest case series to-date indicates that EA is probably an underdiagnosed entity and establishes the demographic and clinical features of EA.

Immunohistochemical features of multifocal melanoacanthoma in the hard palate: a case report.

BACKGROUND: Melanoacanthoma (MA) has been described in the oral mucosa as a solitary lesion or, occasionally, as multiple lesions. MA mainly affects dark skinned patients and grows rapidly, showing a plane or slightly raised appearance and a brown to black color. The differential diagnosis includes oral nevi, amalgam tattoos, and melanomas. We report here the case of a 58-year-old black woman who presented multiple pigmented lesions on the hard palate. CASE PRESENTATION: Based on the differential diagnosis of melanoma, a punch biopsy (4 mm in diameter) was performed. The material was fixed in 10% formalin, embedded in paraffin, and stained with hematoxylin-eosin or submitted to immunohistochemical analysis. Immunohistochemistry using antibodies against protein S-100, melan-A, HMB-45, MCM-2, MCM-5, Ki-67 and geminin was performed. Immunohistochemical analysis revealed strong cytoplasmic immunoreactivity of dendritic melanocytes for proteinS-100, HMB-45 and melan-A.Positive staining for proliferative markers (MCM-2, MCM-5, Ki-67) was only observed in basal and suprabasal epithelial cells, confirming the reactive etiology of the lesion. The diagnosis was oral Melanoacanthoma (MA). CONCLUSION: The patient has been followed up for 30 months and shows no clinical alterations. MA should be included in the differential diagnosis of pigmented lesions of the oral cavity.

Smear cytology findings of large cell neuroendocrine carcinoma of the uterine cervix.

Large cell neuroendocrine carcinoma (LCNEC) of the uterine cervix is a rare tumor. Moreover, there are only three reports to date that have focused on the cytologic findings of cervical LCNEC. We report the case of a 59-year-old Japanese woman with cervical LCNEC combined with small cell carcinoma (SmCC). Cytologic specimens from the uterine cervix demonstrated large cells with coarse chromatin and prominent nucleoli. Frequent mitotic figures were also observed. Curettage of the uterine endometrium revealed an endometrioid adenocarcinoma with squamous differentiation; i.e., an adenoacanthoma. Histologic examination of surgically resected uterine cervical tissue revealed LCNEC with minor foci of SmCC. Neuroendocrine differentiation in LCNEC was confirmed by immunohistochemistry for synaptophysin and CD56. Cytotechnologists or pathologists need to consider a differential diagnosis of LCNEC while examining cervical cytologic specimens; therefore, it is important to correctly identify the cytologic characteristics of this tumor.

From hidroacanthoma simplex to poroid hidradenoma: clinicopathologic and immunohistochemic study of poroid neoplasms and reappraisal of their histogenesis.

BACKGROUND: Poroid neoplasms comprise classic poroma (P), hidroacanthoma simplex (HS), dermal duct tumor (DDT), and poroid hidradenoma (PH). The 3 latter are rarely reported. Poroid cells in P have recently been identified as keratinocytes of the lowermost acrosyringium and the sweat duct ridge. OBJECTIVES: To investigate a large cohort of poroid neoplasms to better define the clinical and pathologic aspects of HS, DDT, and PH. To analyze the expression of discriminatory keratins in all 4 poroid neoplasms. METHODS: 202 P, 11 HS, 17 DDT, 31 PH, and 5 composite tumors were examined under light microscopy, and 11, 9, 10, 15, and 2, respectively, by immunohistochemistry using anti-keratin antibodies, in particular, anti-K77, specific for luminal cells of the eccrine dermal sweat duct, and Ki-67 antibody. RESULTS: HS appeared later in life (66.6 years old) than P, DDT, and PH. Whereas P, DDT, and PH displayed unspecific clinical aspects, HS had most frequently the aspect of a large seborrheic keratosis with well-defined borders. HS, DDT, and PH were absent on palms and soles, but were found on the trunk, the lower limbs, and the upper limbs. Similar pathologic features were observed in all tumors, that is, a majority of poroid cells expressing K14, islands of K10-positive and K77-negative large cells. K77 expression was limited to luminal cells of intact ductal structures within the tumors. CONCLUSIONS: Our data demonstrate the common histogenesis of the 4 poroid neoplasms, which seem to derive from the basal keratinocytes of the sweat duct ridge and the lower acrosyringium. The variable length of the sweat duct ridge may account for the variety of poroid neoplasms, according to the site of tumor induction along this structure.

Expression of keratinocyte growth factor and its receptor in clear cell acanthoma.

The aetiopathogenic mechanism underlying clear cell acanthoma (CCA) is not completely clear and it has been postulated that CCA and psoriasis may have a similar pathogenesis because of the common features shared by the two diseases. As it has been recently demonstrated that in psoriatic lesions the paracrine epithelial growth factors [keratinocyte growth factor (KGF)/fibroblast growth factor (FGF)-7 and FGF-10] are involved in promoting and sustaining the keratinocyte hyperproliferation, the aim of this study was to analyse the expression of KGF on CCA lesions and to search for a role of this growth factor in CCA pathogenesis. Immunohistochemical analysis showed an up-modulation of KGF in CCA, although the immunostaining was variable among the different samples collected. Positive immunoreactivity for KGF was detected mainly on dermal areas where the inflammatory infiltrate was more pronounced suggesting a relationship between lymphocyte activation and KGF up-modulation. Real-time quantitative RT-PCR assay performed on mRNA extracted from formalin-fixed paraffin-embedded CCA and normal skin (NS) samples further demonstrated the overexpression of the KGF/FGF-7 gene in all CCA samples compared with NS. Moreover, the evaluation by immunohistochemistry of KGF receptor distribution, the high-affinity tyrosine kinase receptor for KGF, showed a down-modulation of this receptor, as previously reported in the presence of increased levels of KGF. Taken together these results suggest the inflammatory nature of CCA and further support the hypothesis that this disease may represent, like psoriasis, an inflammatory dermatosis in which KGF up-modulation may be responsible for keratinocyte hyperproliferation and may represent a new common feature of both diseases.

Porocarcinoma arising in pigmented hidroacanthoma simplex.

Hidroacanthoma simplex (HAS) is a rare benign tumor that is also known as intraepidermal poroma. While there have been a few reports of HAS with malignant transformation (porocarcinoma), we report an unusual case of porocarcinoma, arising in a pigmented HAS, the latter also showing secondary amyloid deposits. An 80-year-old Japanese man presented with a cutaneous tumor on his left buttock, which had first been noticed in his childhood. The tumor consisted of flat pigmented plaque and a depigmented papule with erosion. Histologic analysis revealed many pigmented and well-defined nests within the epidermis of the flat pigmented portion. The nests were composed of cuboidal to oval and occasionally elongated, bland, basaloid cells with numerous melanin granules. In addition, there were infrequently ductal structures and small clusters of sebocytes, and abundant amyloid deposits in the upper dermis. These findings were consistent with pigmented HAS with amyloid deposition. In the depigmented portion, markedly atypical cells with occasional ductal structures and intracytoplasmic lumina extended throughout the entire thickness of the epidermis, with minimal invasion of the dermis. We considered this portion of the tumor to be a porocarcinoma. Since the two portions of the tumor were continuous, we made a final diagnosis of porocarcinoma arising in pre-existing pigmented HAS with amyloid deposition.