Jason W. Nash

Correlation between KIT expression and KIT mutation in melanoma: a study of 173 cases with emphasis on the acral-lentiginous/mucosal type

The role of immunohistochemistry in the assessment of KIT status in melanomas, especially acral lentiginous/mucosal, is not well established. Although the reported prevalence of KIT mutations in acral lentiginous/mucosal melanomas is relatively low, detection of mutations in KIT can have profound therapeutic implications. We evaluated the efficacy of immunohistochemistry to predict mutations in KIT. One hundred seventy-three tumors, comprising primary and metastatic melanomas (141 acral lentiginous/mucosal, 5 nodular, 4 lentigo maligna, 3 superficial spreading, 2 uveal, 1 melanoma of soft parts, 8 metastases from unclassified primaries, and 9 metastases from unknown primaries) were studied. Immunohistochemical expression of KIT using an anti-CD117 antibody and KIT mutational analysis by gene sequencing of exons 11, 13, and 17 were performed. Eighty-one percent of acral lentiginous/mucosal melanomas, primary and metastatic, showed KIT expression by at least 5% of the tumor cells. The overall frequency of activating KIT gene mutations in acral lentiginous/mucosal melanomas was 15% (14 out of 91 cases), being the L576P mutation in exon 11 the most frequently detected (4 of 14 cases). Cases showing less than 10% positive tumor cells were negative for KIT mutations. Eighty-two percent (12 of 14) of cases positive for KIT mutation showed KIT expression in more than 50% of the cells. An association between immunohistochemical expression of KIT and mutation status was found (P=0.007). Immunohistochemical expression of KIT in less than 10% of the cells of the invasive component of acral lentiginous/mucosal melanomas appears to be a strong negative predictor of KIT mutation and therefore can potentially be used to triage cases for additional KIT genotyping.

Use of p63 expression in distinguishing primary and metastatic cutaneous adnexal neoplasms from metastatic adenocarcinoma to skin

Absract:  p63, a recently identified homologue of the p53 gene, is mainly expressed by basal and myoepithelial cells in skin. Others and we have shown the value of p63 in distinguishing primary adnexal tumors from visceral adenocarcinomas metastatic to skin. We now investigate the pattern of p63 expression in metastases from skin adnexal carcinomas and their cognate primaries and evaluate p63 expression in a larger case series of malignant cutaneous adnexal neoplasms. Immunohistochemical analysis for p63 was performed on 13 metastases of adnexal carcinomas and their corresponding primary tumors. Twenty visceral metastatic adenocarcinomas to the skin and 7 primary mucinous carcinomas with cutaneous or visceral origin were compared. The majority (90.9%) of primary adnexal tumors strongly expressed p63 and their metastases labeled similar to their cognate primary tumors. With one exception, primary or metastatic mucinous carcinomas did not express p63. Metastases from two apocrine carcinomas lacked p63 expression. All other cutaneous metastases from internal adenocarcinomas were negative for p63. Analysis of p63 expression may assist in the differential diagnosis of primary adnexal carcinomas versus metastatic visceral adenocarcinomas to the skin. Metastases from adnexal carcinomas generally retain p63 expression similar to their associated primary tumors.

Metastatic hidradenocarcinoma with demonstration of Her-2/neu gene amplification by fluorescence in situ hybridization: Potential treatment implications

Abstract:  A 44‐year‐old man was referred for a right chest nodule of 3 months duration. A ‘benign’ nodule had been excised from this location 8 years prior. On examination, palpable nodes were noted in the right axilla. Radiographic studies were significant only for right axillary lymphadenopathy. Histologically, a nodular dermal proliferation composed of poorly differentiated epithelioid cells in nests and focally forming ducts with pseudopapillary architecture comprised the primary tumor. Features of a clear cell hidradenoma were noted focally. Immunohistochemical (IHC) analysis revealed reactivity for HMW cytokeratins, CK5 and CK7, p53, p63, CEA (focal), androgen receptor, EGFR, estrogen receptor (ER), MUC5AC, and strong/diffuse membranous staining for Her‐2/neu. Negative stains included villin, TTF‐1, CDX2, S‐100 protein, vimentin, gross cystic disease fluid protein 15 (GCDFP‐15), mammoglobulin, and MUC2. A wide local excision and axillary node dissection was performed. Metastatic tumor involved nine of 28 nodes. Interphase fluorescence in situ hybridization (FISH) demonstrated chromosomal amplification of the Her‐2/neu locus within the tumor and a nodal metastasis. The patient has completed adjuvant and radiotherapy, including trastuzumab, and is asymptomatic. We believe this to be the first demonstration of Her‐2/neu amplification in a malignant skin adnexal tumor. In analogy to breast carcinoma, these findings suggest the applicability of trastuzumab for patients with metastatic adnexal carcinomas demonstrating Her‐2/neu amplification.

Metastatic basal cell carcinoma exhibits reduced actin expression

Basal cell carcinoma is the most common malignancy in Caucasian individuals. Metastatic basal cell carcinoma is extremely rare (with a rate estimated as 0.03%). Actin has been detected in aggressive forms of basal cell carcinoma, but their expression in metastatic lesions is not known. We compared the expression of actin and actin-related cytoskeletal proteins in relatively less aggressive basal cell carcinoma (nodular), aggressive basal cell carcinoma (infiltrative/morpheaform), and metastatic basal cell carcinoma. We studied 12 cases of nodular basal cell carcinoma, 10 cases of infiltrative basal cell carcinoma, and 10 cases of metastatic basal cell carcinoma with immunohistochemistry for alpha-smooth muscle actin, calponin, myosin, and E-cadherin. Expression was interpreted as positive when at least 5% of the tumor exhibited at least weak expression. Five of the ten patients with metastatic basal cell carcinoma had an antecedent history of radiotherapy. Actin was present in 3 of 12 (25%) of the nodular, all 10 of the infiltrative, and 3 of 10 of the metastatic basal cell carcinomas (P<0.05 for metastatic vs infiltrative and nodular vs infiltrative). Calponin was present in 50% of the nodular, 60% of the infiltrative, and 30% of the metastatic basal cell carcinomas (not statistically significant). Myosin expression was not detected in any of the cases. E-cadherin was present in 75% of the nodular, 70% of the infiltrative, and all of the metastatic basal cell carcinomas (P<0.05 for metastatic vs nodular). Our results suggest that increased actin may contribute to local invasiveness, but it is lost in the metastatic phenotype. History of previous radiotherapy may contribute to development of the metastatic phenotype.

Coexistent psoriasis and lupus erythematosus treated with alefacept

Coexistence of psoriasis and subacute cutaneous lupus erythematosus (SCLE) is unusual. Although there have been reports of this occurrence, there have been no reports of this overlap syndrome treated with immunomodulators. We describe a case of coexisting psoriasis and SCLE initially treated with infliximab, and then alefacept. The patient’s arthritis flared after the second infusion of infliximab, which was discontinued. During treatment with alefacept, the patient’s psoriasis improved markedly without exacerbation of his photosensitive SCLE lesions.

Cutaneous adnexal tumor with an unusual presentation-discussion of a potential diagnostic pitfall

The clinical presentation of skin adnexal tumors is nonspecific, and histologically; the differential diagnosis between primary cutaneous adnexal malignant carcinomas and metastatic tumors with a visceral origin can be challenging. We report a patient with history of invasive ductal carcinoma of the breast who presented with a 1-cm erythematous palpable lesion on her right calf. The biopsy showed an intradermal proliferation of malignant epithelioid cells with ductal differentiation, histologically compatible with metastatic breast carcinoma. However, the tumor cells labeled strongly and diffusely not only for pancytokeratin and cytokeratin (CK7) but also with p63 and CK5/6; carcinoembryonic antigen highlighted the ductal structures. No labeling was seen for mammoglobin, estrogen/progesterone, Her2-neu, S-100 protein, CK20, thyroid transcription factor-1 (TTF-1), and CDX-2. Based on the p63 and CK5/6 positivity, the differential diagnosis also included the possibility of a primary adnexal neoplasm and a complete excision was advised. The reexcision specimen revealed residual infiltrating dermal tumor and an overlying intraepithelial component with marked cytologic atypia and focal duct formation, diagnostic of a primary cutaneous adnexal tumor with ductal differentiation (porocarcinoma). Immunohistochemical studies (like p63 and CK5/6) can help to differentiate a primary cutaneous neoplasm from a metastatic lesion. This discrimination is of a paramount importance because a diagnostic error can result in profound implications for patients assumed prognosis and subsequently applied therapy.

Sweet syndrome associated with celiac disease.

Neutrophilic dermatoses are a spectrum of diseases with varying presentations and similar clinical and histologic features. The association of neutrophilic dermatosis with celiac disease has not previously been described. We report a 43-year-old man with a history of diverticulitis who presented with mildly pruritic, ulcerating pustules of the dorsal hands, face, elbow, and neck, clinico-pathologically consistent with the neutrophilic dermatosis Sweet syndrome. Remission was achieved with prednisone taper, dapsone, and a gluten-free diet.

A black plaque on the toe of a white male

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