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The presence of multiple dermatofibromas is rare and is defined as more than 15 lesions. Multiple clustered dermatofibroma (MCDF) is a distinct entity with only 12 reported cases in the literature. MCDF occurs in healthy individuals of both sexes in the first to third decades on the lower half of the body and portends an excellent prognosis. On histology, MCDF is consistent with benign dermatofibromas. We report a 31-year-old healthy Hispanic woman with a 14-year history of slowly progressive MCDF located on her right hip initially misdiagnosed as dermatofibrosarcoma protuberans. We believe this case represents the 13th report of MCDF in the literature and the second from North America.

Birt-Hogg-Dubé Syndrome is an autosomal dominant condition characterized by a triad of fibrofolliculomas, trichodiscomas, and acrochordons. Since the first description in 1977, many conditions have been described in association with its clinical triad. Recent epidemiological studies have shown a significant association between the occurrence of lesions in the fibrofolliculoma/trichodiscoma category with renal neoplasms and pneumothoracies. The BHD protein folliculin had recently been identified. The histological findings of the clinical lesions are distinctive. We report a patient with a history of melanoma who presented for routine surveillance. Facial lesions in the fibrofolliculoma/trichodiscoma category were identified. Diagnostic work-up revealed concomitant multinodular goiter, pulmonary cyst, and renal mass. The patient later developed pneumothorax. Clinical manifestations, histological findings, associations, management, and a review of the Birt-Hogg-Dubé Syndrome are discussed.

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Summary Desmosomes are intercellular junctions that have been shown to be down-regulated in certain types of carcinoma and that may play a role in suppression of invasion and metastasis. This paper describes an immunohistochemical study of three types of epidermal neoplasms with monoclonal antibody to desmoglein in order to determine how desmosomal staining correlates with the clinical, biological and histopathological features of these neoplasms. Actinic keratosis (AK) is the most common keratinocytic premalignant neoplasm that was reported to have a 10-20% rate of malignant transformation into squamous cell carcinoma (SCC). Keratoacanthoma (KA) is a benign neoplasm that involutes spontaneously after a few months of rapid growth. SCC is a malignant tumour capable of metastasis. Electron microscope studies of KA and SCC showed significantly reduced staining for desmosomes in SCC but not in KA. We have examined staining for desmoglein using the monoclonal antibody 33-3D, a mouse IgM monoclonal antibody, that recognizes the cytoplasmic domains of desmoglein (Dsg)1 and Dsg2 on frozen sections. Immunohistochemical staining of normal skin with this antibody revealed strong pericellular localization of the antigen, outlining the cell membranes of the keratinocytes. A series of 30 AKs, 12 KAs and 24 SCCs was stained immunohistochemically with 33-3D monoclonal antibody. All examined KAs showed extensive pericellular staining for Dsg. By contrast, juxtanuclear staining for Dsg was noted in 12 SCCs, and completely negative staining in seven SCCs. The five remaining SCCs showed focal pericellular staining for the Dsg marker. The most common finding in AK was focal pericellular staining for Dsg, with complete absence of staining in dysplastic areas (25 cases). In five cases negative pericellular staining in dysplastic areas was associated with juxtanuclear accumulation of the Dsg marker. A strong negative correlation between Dsg staining and degree of dysplasia was obtained. The Dsg pattern in KA is similar to normal epidermis and shows a clear difference between KA and SCC. AK has a limited loss of Dsg expression in a SCClike pattern that is congruent with its premalignant nature. As the stain works on frozen tissue, it may be helpful for rapid differentiation in selected cases in cutaneous oncology and Mohs micrographic surgery. This antibody may also have great potential for the detection of the effects of chemopreventive agents in skin cancer.

A case of pseudoepitheliomatous, keratotic and micaceous balanitis (PEKMB) in a 64-year old man is presented. The patient presented with the 2-year history of a slowly enlarging, hyperkeratotic plaque on his glans penis that was compatible with a clinical diagnosis of PEKMB. The lesion has been treated successfully with topical 5-fluorouracil cream, with no evidence of recurrence at 2-year follow-up. Histological examination revealed acanthosis, hyperkeratosis, and pseudoepitheliomatous hyperplasia with no cytological atypia. This rare penile condition was considered pseudomalignant, premalignant, or as a low-grade squamous malignancy. Apart from this patient we comprehensively review previously reported cases, and discuss a possible concept on etiology, diagnosis and treatment of this entity.

Acral peeling skin syndrome (APSS) is a clinically and genetically heterogeneous disorder. We used whole-exome sequencing to identify the molecular basis of APSS in a consanguineous Jordanian-American pedigree. We identified a homozygous nonsense mutation (p.Lys22X) in the CSTA gene, encoding cystatin A, that was confirmed using Sanger sequencing. Cystatin A is a protease inhibitor found in the cornified cell envelope, and loss-of-function mutations have previously been reported in two cases of exfoliative ichthyosis. Our study expands the molecular pathology of APSS and demonstrates the value of next-generation sequencing in the genetic characterization of inherited skin diseases.

Primary cutaneous adenoid cystic carcinoma is a rare skin neoplasm with a high potential for recurrence after local excision. We present a case of a 45-year-old white female with recurrent primary cutaneous adenoid cystic carcinoma of the scalp. The tumor was resected with Mohs surgery in two stages and defect repaired with split-thickness skin graft. There has been no recurrence of the tumor in the 12-month follow-up period.