Pigmented lesions in actinically damaged skin. Histopathologic comparison of biopsy and excisional specimens.

BACKGROUND AND DESIGN: A consecutive sample of 46 cases was collected for comparative histologic evaluation. Results of incisional biopsies of cutaneous pigmented lesions interpreted as lentigo maligna, melanoma in situ, or invasive melanoma, and those suggestive, but not diagnostic, of melanoma were collected. Those lesions that were on actinically damaged skin and in which biopsy was followed by complete excision within 6 months were included. Incisional biopsies that removed greater than 50% of the surface area of the lesion were excluded. RESULTS: Of the excisional specimens, 40% demonstrated histopathologic features more pronounced than those in the biopsy specimens. Areas of invasive melanoma not detected in the biopsy specimens were observed in 20% of the excisional specimens. Accurate diagnosis based on small biopsy specimens was not always possible because of the absence of a classic lentigo maligna histologic pattern in many cases. The most frequent deviation from the pattern was the presence of lentiginous epidermal hyperplasia within these lesions. CONCLUSIONS: These results suggest that limited sampling may be inadequate for an accurate diagnosis of pigmented melanocytic lesions on actinically damaged skin. Areas chosen for biopsy may not contain the most advanced areas histologically and may fail to detect foci of invasive melanoma elsewhere within the lesion.

Small-diameter invasive melanomas: clinical and pathologic characteristics.

BACKGROUND: Most melanomas when first diagnosed clinically are larger than common benign melanocytic nevi ( > 6 mm). Smaller melanomas, however, may occasionally occur. Yet, very little is known about them. OBJECTIVE: To determine the incidence and delineate the clinical and histologic characteristics of small-diameter invasive melanomas. METHODS: Slides of all melanomas diagnosed between 1984-1993 were reviewed and measured. All invasive lesions less than 6 mm were further scrutinized clinically and morphologically. RESULTS: Among 357 invasive melanomas, 16 (4.4%) were less than 6 mm. Most lesions lacked some of the histologic features usually seen in large melanomas. One half of them were over 0.75 mm deep. Patients with small melanomas were on average 15 years younger than those with large lesions. In females, sites on the upper extremities predominate. In females, small melanomas had clinical signs of melanoma, while in males they resembled nevi. CONCLUSION: Melanomas smaller than 6 mm are not rare. Clinicians and pathologists must learn their features in order to diagnose them properly.

Mucinous eccrine nevus.

We report a solitary lesion with histologic characteristics of an organoid nevus occurring on the lower extremity of a forty-seven-year-old woman. This lesion is thought to represent a variant of eccrine nevus composed of an intradermal proliferation of hyperplastic eccrine sweat glands with associated mucinous change.

Lobular capillary hemangioma (pyogenic granuloma) with satellitosis.

We describe a 43-year-old white man who rapidly developed multiple, extensive angiomatous lesions on the temple and scalp after excision of a solitary lobular capillary hemangioma. This is a well-recognized but rare event. Our case differs from previously reported examples in terms of the age of the patient, the location and extent of the lesions, the histologic features in the form of small foci of angiosarcoma-like infiltration, and possibly with respect to the response to therapeutic intervention. Because of the alarming clinical picture produced by multiple lobular capillary hemangiomas, in addition to the occurrence of disturbing histologic features, the benign and self-limited nature of this disease must be emphasized.

Basal cell carcinoma and melanocytic nevus in the same lesion.

We report a case of basal cell carcinoma and intradermal melanocytic nevus in the same lesion. A review of the literature indicates that the simultaneous occurrence of two or more neoplasms in one specimen is a relatively infrequent finding. The pathogenesis of simultaneously occurring neoplasms remains the subject of speculation. Based on currently available evidence, we believe that the coexistence of lesions in this particular patient is most likely coincidental.