Superficial Acral Fibromyxoma: Report of 13 Cases With New Immunohistochemical Findings.

BACKGROUND: Superficial acral fibromyxoma (SAF) is a benign, soft tissue neoplasm preferably located on the digits. METHODS: We collected 13 cases of SAF and evaluated their clinical, histopathologic, and immunohistochemical features. RESULTS: This study included 9 males and 4 females, median age 54 years. The patients presented with a solitary asymptomatic or tender mass, most of them arising on fingers or toes. Histopathologically all lesions consisted of nonencapsulated dermal nodules, composed of spindled cells with variable myxoid and/or fibrotic stroma. Some lesions were well circumscribed (6/12, 50%), whereas other ones appeared poorly demarcated (6/12, 50%). The stroma was predominantly myxoid (53%), myxoid-collagenous (31%) or mostly collagenous (15%). Neoplastic cells expressed immunoreactivity for CD34 (8/11), CD99 (9/12), and nestin (7/7); whereas MUC4 (0/11) and Bcl-2 (0/7) resulted negative. CONCLUSIONS: Nestin is the best immunohistochemical marker for SAF with higher sensitivity than CD34, although nestin is also positive in dermatofibrosarcoma protuberans and therefore is not helpful in differential diagnosis between SAF and dermatofibrosarcoma protuberans. Cellular digital fibromas and acquired reactive digital fibroma probably are neoplasms closely related to SAF. The homogeneous reactivity for CD99, the negativity for Bcl-2 and lack of the honeycomb infiltration of the subcutis help to rule out myxoid dermatofibrosarcoma protuberans, whereas the negativity for MUC4 and Bcl-2 are helpful tools to rule out low-grade fibromyxoid sarcoma and spindled-cell lipoma, respectively.

Anti-NXP2-Positive Paraneoplastic Dermatomyositis With Histopathologic Changes Confined to the Acrosyringia.

BACKGROUND: Paraneoplastic syndromes consist of a group of disorders that are not related to the extension of the primary tumor or its metastases and that might be the first manifestation of a hidden neoplasm. It is a well-known association between dermatomyositis (DM) and cancer, especially gynecological tumors in women and lung cancer in men. METHODS: We describe the case of a 67-year-old male who developed muscular weakness and pruritic skin lesions. Skin biopsies were performed and histologic findings were consistent with DM. RESULTS: Skin biopsy showed interface dermatitis with vacuolar degeneration of the basal layer, dermal mucin deposits, and necrotic keratinocytes in the acrosyringia, a finding that has been previously reported in lupus erythematous but not in DM. Autoimmunity tests showed positivity for antinuclear antibodies and anti-NXP2, a recently described antibody associated with juvenile DM and, more rarely, with paraneoplastic DM. CONCLUSION: We present the first case in the literature with histopathologic changes of DM affecting the acrosyringia. Besides, our patient autoimmunity results support the utility of the new myositis-specific autoantibodies and its relation with a clinical phenotype.

Acantholytic-like malignant melanoma: an unusual morphologic variant.

We report the case of a primary cutaneous melanoma with acantholytic-like changes in a 61-year-old man. Clinical and immunohistochemic features were similar to those of other superficial spreading with vertical growth melanomas. Histologically, intraepidermal and suprabasal bullous spaces were filled by isolated tumor cells, simulating acantholytic blisters. These findings could be explained by the presence of inflammation-related extracellular fluid. Two other cases with suprabasal discohesive atypical melanocytes have recently been described. We report the first case of malignant melanoma with an intense and diffuse pattern of dyscohesion, resembling acantholysis. Recognition of this histologic pattern in malignant melanoma is important to avoid a misdiagnosis.

Mask-like metastasis: report of 2 cases of 4 eyelid metastases and review of the literature.

Bilateral periorbital edema and swelling are frequent in clinical practice and are commonly attributed to orbital contact dermatitis due to different drugs and cosmetic products. However, when there is a background of a solid cancer, the possibility of eyelid metastasis should be also considered. Metastases to the eyelids are rare, and in most cases, these lesions are unilateral. Because only a few cases of bilateral involvement have been reported in the literature, clinical and morphological data of this variant are under recognized. We report the clinical and histopathological characteristics of 2 patients with 4 eyelid metastasis and review the previous cases reported in the literature.