Giant cell collagenoma in a patient with Cowden syndrome: A rare case report and literature review with a focus on the spectrum of sclerotic fibroma and giant cell collagenoma.

Sclerotic fibroma (SF) is a rare subset of dermal fibromas that occurs sporadically or in association with Cowden syndrome (CS). We report a case of a patient with known CS and a solitary lesion on the scalp. Histologic examination demonstrated a well-circumscribed lesion with sclerotic dermis and a whorled collagen pattern, multinucleated giant cells, and dendritic spindle cells. Nuclear atypia or mitotic figures were not noted. The giant cells were negative for Melan-A, SOX-10, EMA, SOX-10, and factor XIIIa. These findings are consistent with a giant cell collagenoma (GCC). Despite possible overlap with SF, GCC has not been associated with CS. This makes our case unique and suggests that GCC should be included in the spectrum of CS-associated cutaneous lesions. The diagnosis of SF may lead to the identification of previously undiagnosed CS; accordingly, GCC, even when present as a solitary lesion, may indicate the need for further work-up and screening for CS.

Assessment of lipid and pigment content in suspicious melanocytic lesions to improve melanoma detection.

Melanoma is a highly aggressive form of skin cancer and the most frequent lethal malignancy diagnosed by dermatologists. Although there have been advances for predicting melanoma prognosis, there are few highly sensitive and specific diagnostic tools for clinically evaluating suspicious melanocytic lesions prior to biopsy. We have recently determined that alterations in cellular lipid and pigment content are associated with tumor progression and melanoma metastasis. Here, we seek to determine if lipid droplet and pigment content assessments near the skin's surface are able to distinguish benign from malignant melanocytic lesions. We obtained 14 benign melanocytic lesions, classified as Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) class 1, and 22 malignant melanomas, classified as MPATH-Dx class 4 or 5, from Boston Medical Center. The malignant melanomas had an average greatest thickness of 1.8 ±â€…2.1 mm with 7/22 biopsies showing the presence of ulceration. Tissues were stained with the Fontana Masson stain to detect pigment or immunohistochemically stained for adipophilin, the main protein component of lipid droplets, to detect lipid droplets. Pigment and lipid droplets were quantified using ImageJ and CellProfiler, respectively. We found no significant difference in total pigment area between benign melanocytic lesions and malignant melanoma, and a 66% decrease in lipid content and 68% reduction in lipid/pigment content between benign melanocytic lesions and malignant melanoma ( P  < 0.05). Our results suggest that lipid content and lipid/pigment content ratios may distinguish benign and malignant melanocytic lesions, which may be useful as a diagnostic tool for histopathologically challenging pigmented lesions.

Clear Cell Acanthoma with Malignant Cytologic Features: A Case Report and Review of the Literature.

Clear cell acanthoma (CCA) is classically considered a benign epidermal tumor, although rare case reports have described CCA with malignant features. Here, we present a case of a patient with a biopsy proven CCA that regrew post-biopsy and was subsequently completely excised. Histologic examination of the tumor in the excision specimen revealed malignant cytologic features that were not present in the initial biopsy. A review of the literature identified five additional cases of CCA with similar malignant cytologic features. On analysis, common histopathologic characteristics included cellular pleomorphism, increased nuclear-to-cytoplasmic ratio, prominent nucleoli, and atypical mitotic figures. We support the designation of atypical clear cell acanthoma for these entities with features of both CCA and significant cytologic atypia. As none of these cases exhibited clinically aggressive behavior, further study is warranted.

Melanocytic matricoma with atypical features: A case of malignant melanocytic matricoma?

Melanocytic matricoma is a rarely reported, benign cutaneous adnexal neoplasm composed of epithelial cells exhibiting differentiation towards hair matrix as well as admixed, pigmented, dendritic melanocytes. The proposed malignant counterpart to melanocytic matricoma, malignant melanocytic matricoma (MMM), is even more rare. Here we report a case of a melanocytic matricoma with atypical features in a 92-year-old female with a 1.2-cm pigmented nodule on the right nasal sidewall. Histopathology revealed a well-circumscribed dermal tumor composed of atypical matrical cells with scattered aggregates of anucleate keratinocytes (ghost cells), prominent intratumoral pigment, numerous mitotic figures (88 mitosis/10 high-power field [HPF]), and intermixed dendritic melanocytes. A literature review was performed for MMM to determine if the current case fit diagnostic criteria for this entity. Including the current case, 12 cases of MMM were identified and analyzed to investigate common clinical and histopathologic features. MMM commonly occurred on the head and neck (7/12 cases) of older individuals (median age of 80) with a slight male predominance (male-to-female ratio of 3:1) and on histopathology presented as a multinodular dermal tumor composed of mitotically active (average mitotic rate of >50 mitoses/10 HPF) pleomorphic epithelial cells with foci of ghost cells. Dendritic melanocytes were found throughout the tumor lobules in all cases. Given that only two of 12 cases have exhibited locally aggressive behavior, further study is warranted to determine the true malignant potential of MMM.

Diagnostic Value of Plasmacytoid Dendritic Cells in Differentiating Pityriasis Lichenoides et Varioliformis Acuta From Lymphomatoid Papulosis.

ABSTRACT: Pityriasis lichenoides et varioliformis acuta (PLEVA) and lymphomatoid papulosis (LyP) can often demonstrate clinical and histopathologic overlap. A recent study demonstrated significant plasmacytoid dendritic cell (pDC) recruitment in lesions of PLEVA, whereas another study reported minimal pDC recruitment in lesions of LyP. To confirm the possible diagnostic value of pDCs in differentiating PLEVA and LyP, we compared the presence and distribution of pDCs and myxovirus protein A (MxA) expression (an indirect assessment of pDC activity). In total, 19 cases of PLEVA (16 patients) and 14 cases of LyP (11 patients) were examined using immunohistochemical stains for anti-blood-derived dendritic cell antigen-2 and MxA. Individual semiquantitative scoring systems were used to assess the immunohistochemical results, and a Mann-Whitney test with a subsequent 2-tailed P test was performed for statistical analysis. No statistically significant difference in the number of pDCs in both groups was found. However, most PLEVA cases (84%) demonstrated intense and diffuse MxA expression, whereas LyP cases (71%) demonstrated weak patchy staining (P < 0.007). Our study suggests that although additional studies may be needed to determine whether pDCs are more relevant to the pathogenesis of PLEVA or LyP, pDC activity through MxA staining may play a role in differentiating PLEVA from LyP and may serve as a platform for additional studies.

Early Erythema Migrans: Do Not Count on Plasma Cells.

ABSTRACT: Three hundred thousand new cases of Lyme disease are diagnosed annually in the United States. The earliest manifestation of the disease, erythema migrans, occurs earlier than serologic conversion, and skin biopsies can be very helpful in suggesting the diagnosis. Histopathologic findings vary depending on where in the lesion the specimen is taken, but typically consist of a superficial and deep perivascular and interstitial lymphocytic infiltrate with eosinophils centrally and with histiocytes and plasma cells at the periphery. Rare cases with interstitial histiocytes and rare-to-sparse plasma cells exist. We present a 67-year-old man whose skin biopsy, taken on day 2 of his eruption, demonstrated a subtle perivascular and interstitial infiltrate of histiocytes without plasma cells. Dermatopathologists need to be aware of this pattern and consider the diagnosis of erythema migrans, despite negative initial serologic testing.

Merkel Cell Carcinoma In Situ: No More Serendipity?

ABSTRACT: A 50-year-old man, with a history of extensive sun exposure and multiple previous non-melanoma skin cancers, presented with an asymptomatic 8-× 10-millimeter scaly, skin-colored papule on his right shoulder. Subsequent biopsy and excision revealed epidermal hyperplasia containing large atypical basaloid cells with pagetoid spread. Immunoperoxidase staining for cytokeratin-20 demonstrated a focal perinuclear dot-like pattern, and after excluding other in situ entities, a diagnosis of Merkel cell carcinoma In Situ (MCCIS) was rendered. MCCIS is a very rare entity. Although approximately 18% of Merkel cell carcinomas have epidermal involvement, currently only 17 cases of MCCIS have been reported, of which only 7 had no associated neoplasm. Previously, MCCIS was considered a serendipitous or incidental finding, as most cases co-existed with squamous cell carcinoma in situ. This case is unique in that it was not associated with a squamous lesion, and in addition, the pagetoid spread was unusual and has only occasionally been described. As such, MCCIS should be added to list of in situ epidermal lesions with pagetoid spread.