Regression in cutaneous melanoma: a comprehensive review from diagnosis to prognosis

Abstract

Histological regression in primary cutaneous melanoma occurs in 10-35% of cases. Although a large body of literature exists to suggest that histological regression serves very little purpose in predicting biologic behaviour with melanoma, recognizing the presence of regression at clinical and histological ground may still retain some value in grading melanoma aggressiveness. In the current review, a comprehensive overview of the main aspects of regression will be provided. Histologically, many classifications have been reported so far, but all of them only agreed on the presence of an infiltrate of lymphocytes admixed with pigment-laden macrophages underlying an atrophic epidermis with flattened rete ridges. Upon dermoscopy, regression is also named Blue White Scar-like areas and could be variably admixed with granularity or peppering. Almost fully regressed lesions represent a main diagnostic issue in dermoscopy, and thus, confocal microscopy can be of help to identify whether the tumour is melanocytic or not. The clinical utility of regression as a prognostic factor has been challenged recently. Nowadays, evidences showed that it is less likely associated to SLN metastases.

Unknown Primary Melanoma: Worldwide Survey on Clinical Management

“…Furthermore, histological regression has been described as a potential favorable feature of melanoma as it probably reflects an activation of the immune system [13] . On the other hand, discordant data are reported regarding the survival of patients with complete regressed primary cutaneous melanoma [14] .…”

“…The great majority of patients with MUPs had skin metastases as first disease manifestation (51 cases), followed by nodal (41), visceral (32), and mucosal metastases (14).…”

Metastatic thyroid carcinoma without identifiable primary tumor within the thyroid gland: a retrospective study of a rare phenomenon

“…The other possibility is tumor regression. Spontaneous tumor regression, defined as diminution of a malignant neoplasm as a consequence of host response, is a common phenomenon affecting 10–35% cutaneous melanoma (15, 16), and has also been reported in certain carcinomas, e.g. Merkel cell carcinoma (17), hepatocellular carcinoma (18), and renal cell carcinoma (19).…”

“…Merkel cell carcinoma (17), hepatocellular carcinoma (18), and renal cell carcinoma (19). The histologic features of melanoma regression are fibrosis, often in association with lymphocytes or macrophages (16). In our cohort, five of seven patients had evidence of fibrosis in their thyroid: four in association with benign thyroid disease while the other displayed a 0.2 cm unifocal stellate fibrosis.…”

Metachronous Spontaneous Remission of Melanoma Lung Metastasis and Mediastinal Lymph Node Metastases

“…Clinically, partial regression is mainly characterized by whitish and grayish areas of pigmentation. Histopathologically, the process starts with a dense infiltrate of lymphocytes and ends with fibrosis and/or melanosis within a thickened papillary dermis [11]. Recent studies cast doubt on the potential negative prognostic implication of partially regressive MM primary lesions and suggested a protective effect [12].…”