Rate of Immunohistochemistry Utilization in the Diagnosis of Cutaneous Melanocytic Lesions.

ABSTRACT: Melanocytic lesions represent a large portion of the workload in many laboratories. Although many melanocytic nevi can be confidently diagnosed based on routine hematoxylin and eosin light microscopy, ancillary testing is often warranted. Various immunohistochemical (IHC) stains are routinely used in the diagnosis of melanocytic lesions. Because melanocytic lesions are frequently encountered in skin specimens, the use of IHC is likely to represent a significant area of resource utilization in dermatopathology laboratories. Our study investigates the rate of IHC utilization in the diagnosis of melanocytic lesions in a high-volume, government-funded, not-for-profit laboratory. Of the 1230 cases of melanocytic lesions investigated, including benign as well as malignant entities, 300 cases involved the utilization of IHC. IHC was used in a larger percentage of melanomas than nevi and in a larger percentage of melanoma in situ cases than invasive melanomas. SOX10 was overwhelmingly the most frequently used IHC.

Cutaneous lupus erythematosus of the eyelid as a mimic of squamous epithelial malignancies: a clinicopathologic study of 9 cases.

PURPOSE: To describe 9 cases of chronic cutaneous lupus of the eyelid, its potential similarities with squamous epithelial malignancies, and clinical and histopathologic features that assist in distinguishing lupus from epidermal neoplasia. METHODS: The authors identified and reviewed 9 cases of cutaneous lupus involving the eyelid at their institutions since 1991. Published cases of cutaneous lupus involving the eyelid were identified using Ovid MEDLINE and PubMed and references within the articles. RESULTS: The average patient age at presentation was 52 years old (range 33-89) with a female-to-male ratio of 8:1. The right lower eyelid was the most commonly affected location, with 44% of the cases occurring at this site. Lesions had been present on average for 2.5 years prior to presentation (range 2-60 months). Lesions were clinically heterogeneous, ranging from macules to crusted shallow ulcers. In 44% of cases, the preoperative clinical diagnosis was that of either squamous cell carcinoma or basal cell carcinoma. The patients thought to have a skin malignancy were 10 years older at presentation, more likely to be male, and more likely to have ulcerative lesions with rapid onset when compared with the other lupus patients. CONCLUSIONS: A subset of patients with lupus (particularly discoid lupus) involving the eyelid have clinical features mimicking patients with squamous epithelial malignancy. In cases such as these, biopsies are critical for establishing the diagnosis and pursuing appropriate therapeutic approaches.

Cutaneous lupus erythematosus simulating squamous neoplasia: the clinicopathologic conundrum and histopathologic pitfalls.

BACKGROUND: The clinical distribution and character of cutaneous lupus erythematosus lesions can simulate squamous neoplasms, leading physicians to submit a shave biopsy specimen with a differential diagnosis of squamous neoplasm. OBJECTIVE: Our aim was to describe histologic features of interface dermatitis that cause difficulty in distinguishing between cutaneous lupus erythematosus and squamous neoplasia in shave biopsy specimens and to identify distinguishing criteria. METHODS: Twenty-six biopsy specimens from 10 patients initially diagnosed with squamous neoplasia that ultimately proved to be cutaneous lupus erythematosus were identified. Comparisons were made of these to 38 control biopsies of chronic cutaneous lupus erythematosus and 34 control biopsies of keratoses/carcinomas without lupus. All biopsies were scored (0 or 1: absent or present) with respect to 11 histologic criteria. RESULTS: The criteria of perifollicular inflammation, follicular plugging, vacuolar interface change, compact orthokeratosis, and acrosyringeal inflammation were significantly more common in the lupus cases than in the keratoses/carcinomas controls. The mean lupus case score was 6.88, lupus control score 6.55, and keratoses/carcinomas control score 5.08. LIMITATIONS: A limited number of patients were studied. Microscopic observations and assumptions with inherent subjectivity were used in establishing the histologic scores. CONCLUSION: Use of the criteria presented, although not absolute, should alert one to the possibility of lupus in an atypical squamous proliferation, especially in suspected squamous neoplasms that worsen or recur after therapy.

Cutaneous clear-cell granular cell tumors: the histologic description of an unusual variant.

BACKGROUND: Granular cell tumors (GCTs) are neoplasms showing nerve sheath differentiation that can arise in the skin but, to our knowledge, have not been associated with significant clear-cell morphology. METHODS: Two patients developed four separate GCTs with distinctive, diffuse clear-cell change, which completely camouflaged the primary differentiation. The morphology, histochemistry and immunohistochemistry of the lesions are described and are compared with the presence and extent of clear-cell change in 14 other cases of GCTs. RESULTS: The index cases were relatively broad proliferations with uniform diffuse clear-cell change and only minimal overlying epidermal hyperplasia. Prominent lymphoid nodules were present at the periphery. These clear-cell granular tumors were positive for S-100 protein, p75, CD68, NKI/C3 and neuron-specific enolase and were negative for epithelial mucin, periodic acid-Schiff, carcinoembryonic antigen, HMB-45, Melan-A, smooth muscle actin, Leu7, synaptophysin, CD34, factor XIIIa, epithelial membrane antigen and cytokeratin. Three of the fourteen comparison cases were found to have no clear-cell change, eight showed focal clear-cell change and three showed moderate clear-cell change. CONCLUSIONS: The distinctive morphology and the immunohistochemical results are discussed in the context of the differential diagnosis of clear-cell cutaneous tumors.

Cutaneous leiomyoma with cytologic atypia, akin to uterine symplastic leiomyoma.

BACKGROUND: Smooth muscle tumors of the skin with cytologic pleomorphism and mitotic activity have traditionally been characterized as leiomyosarcomas, despite having a benign clinical course. In the uterus, there is a smooth muscle tumor known as symplastic leiomyoma, which typically has cytologic pleomorphism without significant mitotic activity. OBJECTIVE: The objective was to illustrate by case report the unusual histologic variant of the cutaneous pilar leiomyoma analogous to the symplastic leiomyoma of the uterus. METHODS: A 54-year-old woman presented with a clinical picture of cutaneous leiomyoma but had histologic features of nuclear hyperchromasia and pleomorphism, but rare mitoses. RESULTS: Management of this patient included excision of the involved area. CONCLUSION: Symplastic leiomyoma is an atypical uterine leiomyoma with cytologic atypia. We present the case of a patient with cutaneous leiomyomas that histologically demonstrated similar features to a uterine symplastic leiomyoma. We believe that this represents a distinct histologic variant of the cutaneous pilar leiomyoma analogous to the symplastic leiomyoma of the uterus.