Primary Dermal Melanoma in a Patient with a History of Multiple Malignancies: A Case Report with Molecular Characterization
A 72-year-old Caucasian woman came to our attention for a right paravertebral purplish-red nodular lesion on the back, with a few focal pigmentations and a small semilunar perinodular area of brownish pigmentation (fig. ). The patient could not report the onset of the lesion. The differential diagnosis included, in this case, basal cell carcinoma, malignant melanoma, vascular lesions, epidermoid carcinoma and dermatofibroma.\nThe patient's clinical history was characterized by multiple tumours, including bilateral metachronous breast cancer for which she had undergone bilateral mastectomy and axillary lymphadenectomy, clear cell renal cell carcinoma, uterine fibromatosis and intestinal polyposis with low- and high-grade dysplasia. Despite the macroscopic aspect which suggested pigmented basal cell carcinoma, the possibility of the lesion being melanocytic made us opt for an excisional biopsy with a 2-mm margin.\nThe skin lesion specimen showed a poorly differentiated neoplastic dermal infiltration with morphological aspects of melanocytic proliferation (fig. ). The tumour cells displayed round or oval shapes with brisk mitotic activity, and they were arranged in a nodular architecture with rounded margins. Lymphocytic and plasmacellular infiltration of the lesion was observed, without formation of lymphoid nodules. An intraepidermal component, ulceration and regression aspects were not evident, even with an examination of multiple sections; a preexisting nevus, spindle neoplastic cells or bands of mature intercellular collagen were also not found. A distinct grenz zone was appreciable between the dermal neoplasm and the overlying epidermis. The neoplastic cells demonstrated melanocytic-type immunohistochemistry (S100 protein and HMB-45 positive). The proliferative index evaluated with Mib-1 was 25%.\nThe histopathological report was summarized as ‘malignant melanoma (thickness 2 mm); the absence of intraepidermal atypical melanocytes is compatible with metastatic malignant melanoma or PDM’. Desmoplastic melanoma was excluded on the basis of cytology and because of the lack of a desmoplastic reaction, while nodular melanoma was excluded due to the absence of an intraepidermal component. With the aim of identifying a possible primary lesion, the following tests were performed: dermatological examination; total body CT; ophthalmologic examination; pancolonoscopy; ear, nose and throat examination; esophagogastroduodenoscopy, and gynaecological examination. No evidence of another primary melanoma was found; however, a parallel finding of frontal meningioma was noted. The absence of another primary lesion led us to make the diagnosis of PDM per exclusionem.\nThe second surgical step included the excision of the biopsy scar with 2-cm margins and sentinel lymph node biopsy. The preoperative lymphoscintigraphy showed 3 areas of uptake − 2 of them involving the soft tissue at the level of the posterior pillar of both the axillae, and the remaining 1 in the left paravertebral area, adjacent to the previous surgical site. However, only a single sentinel node presenting micrometastasis of melanoma was found in the latter area.\nA bilateral axillary ultrasound examination was performed to investigate the areas of lymphoscintigraphic uptake; subsequently, the patient underwent an additional surgical procedure for the removal of a lymph node with ambiguous ultrasonographic features found within the residual left axillary fatty tissue (the patient had had ipsilateral axillary lymphadenectomy several years before for breast cancer). The histological examination of the specimen revealed adipose tissue and a lymph node with reactive patterns. The patient is currently alive and free of disease 14 months since her diagnosis.