Clinical and dermoscopic characteristics of desmoplastic melanomas.

OBJECTIVE: To describe and analyze the clinical and dermoscopic characteristics of desmoplastic melanoma (DM) as a function of pathologic subtype and phenotypic traits. DESIGN: Retrospective case series. SETTING: Eight high-risk dermatology clinics. PATIENTS: Patients with DM confirmed by histopathologic analysis whose records included a high-quality dermoscopic image. MAIN OUTCOME MEASURES: Clinical, dermoscopic, and histopathologic features of DM. RESULTS: A total of 37 DM cases were identified. The majority of patients had fair skin, few nevi, and no history of melanoma. Lentigo maligna was the most frequent subtype of melanoma associated with DM. The most frequent clinical presentation of DM was a palpable and/or indurated lesion located on sun-exposed skin. Forty-three percent of cases were classified as pure DM, and 57% as mixed DM. Pure DM lesions were thicker than mixed DM lesions (4.10 vs 2.83 mm) (P = .22) and were less likely to have an associated epidermal non-DM component (63% vs 100%) (P = .004). Dermoscopically, DMs had at least 1 melanoma-specific structure, the most frequent being atypical vascular structures. Peppering was more frequently seen in pure DM (44% in pure DM vs 24% in mixed DM) (P = .29). In contrast, crystalline structures, polymorphous vessels, and vascular blush were more commonly seen in mixed DM. CONCLUSIONS: Though DM can be difficult to diagnose based on clinical morphologic characteristics alone, dermoscopy has proved to be a useful aid during the evaluation of clinically equivocal lesions or those lesions with a benign appearance. The most common dermoscopic clues observed in DMs included atypical vascular structures, peppering, and occasionally other melanoma-specific structures.

Desmoplastic melanoma: a review.

Desmoplastic melanoma (DM) is a variant of spindle cell melanoma typically found on chronically sun-damaged skin of older individuals. Early diagnosis can be challenging because it is often amelanotic and has a predominantly dermal component. DM can be difficult to diagnose not only clinically but also histologically, and can be mistaken for a variety of benign and malignant nonmelanocytic spindle cell tumors when viewed on prepared histopathology slides. Pathologists have observed that DMs can manifest significant variation with respect to the extent of intratumoral cellularity, fibrosis, and/or perineural invasion. Furthermore, some tumors present with a pure desmoplastic invasive component (>90%) while other tumors display mixed features of DM and nondesmoplastic melanoma. This has led to the separation of DM into 2 histologic subtypes, pure and mixed. With a focus on the distinction between pure and mixed DM, this review will detail what is currently known about the diagnostic features of DM, discuss risk and prognostic factors, and examine the current literature on disease progression and management.

Pigmented spindle cell naevus of Reed: a controversial diagnostic entity in Australia.

BACKGROUND/OBJECTIVES: The Reed naevus or pigmented spindle cell naevus of Reed (PSCN) was previously considered a pigmented variant of the spindle cell-type of Spitz naevus. It is now considered a distinct entity and may overlap with cutaneous melanoma in both clinical and dermatoscopic features. We hypothesised that PSCN is an under-recognised entity in Australia and present a typical case. To test our hypothesis, we performed a clinically based survey of Australian dermatology trainees (Registrars). A further aim of our study was to determine the approach of dermatology trainees in this country to the management of this type of lesion. METHODS: A web-based survey questionnaire based on the presented case was circulated to trainees of the Australasian College of Dermatologists. Responses, including level of training and initial approach to management, were collated and form the basis of the results presented herein. RESULTS: Of 39 respondents, 13 (33%) diagnosed the lesion as PSCN. The majority (33/39; 84.6%) indicated they would biopsy the lesion, with most of these (91%) preferring excisional biopsy. CONCLUSIONS: The results support our hypothesis that PSCN is under-recognised in Australia. The results also show that despite difficulty distinguishing this lesion, management of these lesions by dermatology trainees in Australia is consistent and parallels current recommendations.

Pigmented lesions in adolescents.

Accurate diagnosis of congenital and acquired pigmented lesions accompanied by an understanding of their natural history and disease associations is critical for the appropriate management and counseling of adolescents, as well as timely referral to specialists when indicated. The recognition of atypical nevi and other melanoma risk factors in adolescents should lead to institution of preventive measures, such as routine skin examinations and counseling regarding sun protection. Because the incidence of melanoma is increasing in adolescents as well as adults, prompt identification of suspicious melanocytic lesions may lead to early diagnosis and effective treatment of melanoma. Numerous pigmented lesions can also herald the presence of a multisystem disorder; the recognition of syndromes associated with these lesions should result in appropriate evaluation and genetic counseling of affected individuals. This review distinguishes pigmented lesions that histologically represent a proliferation of melanocytes and that may therefore confer an increased risk for melanoma, from pigmented lesions due to increased melanization alone (i.e., increased melanin content) that are not associated with malignancy.