Role of Wnt signaling in dermatofibroma induction phenomenon.

BACKGROUND: Dermatofibroma (DF) is a common benign skin neoplasm. Induction above DF lesions, including follicular unit induction, is a frequently observed phenomenon. Wnt signaling is known to be critical in hair follicle morphogenesis. Our study assesses the role of Wnt signaling in DF induction by evaluating intracellular localization of ß-catenin in various types of DF induction. METHODS: Archived tissue collected between 1 October 1980 and 1 October 2013 was stained per protocol using hematoxylin and eosin and anti-ß-catenin monoclonal antibody. Specimens were grouped into categories based on the presence or absence and type of induction. All specimens were scored for nuclear ß-catenin localization. RESULTS: Of 62 specimens, 42 (68%) showed induction while 20 (32%) showed none. Nuclear ß-catenin staining was detected in 23 (55%) of the induction and in none of the no-induction specimens (P-value < 0.001). Types of induction included: 15 (24%) follicular induction, 31 (50%) acanthosis, and 4 (6%) sebaceous induction. For follicular induction, 13 (87%) showed positive nuclear ß-catenin staining compared to 11 (35%) for acanthosis and 1 (25%) for sebaceous induction (P-value = 0.002). CONCLUSION: Our findings support the hypothesis that DFs promote an ectopic activation of Wnt pathway signaling in follicular induction phenomenon.

Melanocytic tumors with intraepidermal melanophages: a report of five cases with review of 231 archived cutaneous melanocytic tumors.

Dermal melanophages are frequently encountered in both benign melanocytic nevi and malignant melanoma. In contrast, intraepidermal melanophages (IEM) are under-recognized in melanocytic lesions and their biologic significance is not understood. Herein, we report the clinical and histopathologic features of five melanocytic lesions featuring IEM encountered prospectively in our dermatopathology practice at the University of Chicago. Two hundred and thirty-one (231) archived skin primary melanocytic proliferations were also investigated retrospectively in a de-identified, archival teaching set collection. Nineteen of 231 of the archived cases were positive for IEM. Among the total 24 IEM-positive cases (5 prospective and 19 archived cases), 13 were categorized as Spitz nevi (p < 0.0001) and 3 as atypical Spitz tumors (p = 0.0152). Fourteen of 24 cases with IEM also exhibited intracorneal melanocytes (p < 0.0001). IEM are evidently not rare, especially in spitzoid melanocytic neoplasms. IEM in our series were significantly correlated with intracorneal melanocytosis, possibly indicating an association between IEM and suprabasal melanocytosis and/or transepidermal elimination of melanocytes.

Early morphea simulating patch-stage mycosis fungoides.

Morphea is a rare fibrosing condition of the skin and underlying tissues characterized histopathologically by thickened collagen bundles throughout the dermis, loss of adnexal structures, and "fat trapping." In the early stages of morphea, the absence of the fully developed characteristic findings may cause diagnostic confusion for the practicing pathologist. The authors report an unusual case of early morphea misdiagnosed as patch-stage poikilodermatous mycosis fungoides (MF) based on the initial clinical, histopathologic, and molecular findings. However, as time elapsed, well-developed lesions revealed clinical and histopathologic features diagnostic of morphea. The authors report this case to illustrate that lesions of early morphea may simulate MF. Given the similarities in clinicopathologic presentation, dermatologists and dermatopathologists should be cautious not to inadvertently misinterpret early morphea as MF.

Cutaneous and systemic hypersensitivity reactions to metallic implants.

Cutaneous reactions to metal implants, orthopedic or otherwise, are well documented in the literature. The first case of a dermatitis reaction over a stainless steel fracture plate was described in 1966. Most skin reactions are eczematous and allergic in nature, although urticarial, bullous, and vasculitic eruptions may occur. Also, more complex immune reactions may develop around the implants, resulting in pain, inflammation, and loosening. Nickel, cobalt, and chromium are the three most common metals that elicit both cutaneous and extracutaneous allergic reactions from chronic internal exposure. However, other metal ions as well as bone cement components can cause such hypersensitivity reactions. To complicate things, patients may also develop delayed-type hypersensitivity reactions to metals (ie, in-stent restenosis, prosthesis loosening, inflammation, pain, or allergic contact dermatitis) following the insertion of intravascular stents, dental implants, cardiac pacemakers, or implanted gynecologic devices. Despite repeated attempts by researchers and clinicians to further understand this difficult area of medicine, the association between metal sensitivity and cutaneous allergic reactions remains to be fully understood. This review provides an update of the current knowledge in this field and should be valuable to health care providers who manage patients with conditions related to this field.