Synchronous Melanoma: Definition, Prognosis, and Implications. A Comprehensive Review of Literature

Background

Although multiple primary melanomas (MPMs) have been reported in the literature, the subgroup of synchronous melanomas (SMs) remains understudied.

Methods

We conducted a comprehensive systematic review of the English literature from 1972 to 2023 to characterize SM. Our objective was to clarify the definition, determine incidence and prognosis, and present recommendations.

Results

We found 18 case series articles and six case reports that met our criteria. Twelve of eighteen studies defined SM as a second primary melanoma identified within 1 month. The total number of SM patients reported was 1083. The cumulative percentage of MPM in total melanoma patients was 2.9 %, and the cumulative percentage of SM patients in MPM patients was 31.3%. SM patients trended toward higher body anatomical concordance, older age, and male sex. Despite limited data, SMs do not show a worse prognosis for patients compared with single melanomas.

Conclusions

Despite a lack of consensus in the past, we recommend that SM be defined as a second primary melanoma detected within 1 month of the initial diagnosis. SMs comprise almost one-third of MPM cases and do not seem to carry any worse prognosis than the patients presenting with single melanoma. We believe older age and male sex may be more prone to SM. We recommend patient education, self-skin evaluations and TSE at initial and follow-up visits. Neither randomized controlled trials nor meta-analyses on SM exist. Ideally, further studies with a large cohort of patients are needed to accurately define SM.

Partial unilateral lentiginosis: a clinicopathological analysis of 32 cases on the head and neck area in Korea

BACKGROUND

Partial unilateral lentiginosis (PUL) is a rare acquired circumscribed hyperpigmentation characterized by multiple simple lentigines involving half of the body. Since the previous studies of PUL were mostly based on case reports and the current literature lacks well-designed retrospective studies that involve a large number of cases, PUL is not a well-defined entity, and differential diagnosis with nevus spilus is still difficult. This study aims to evaluate clinical and histopathological characteristics and treatment outcomes of PUL on head and neck area of Koreans.

METHODS

Thirty-two patients with PUL on head and neck area were diagnosed clinicohistopathologically at the Asan Medical Center from 2004 to 2017. Their medical records, photographs, and biopsy specimens were reviewed, and immunohistochemical staining for protein kinase C (PKC)-βΙΙ was evaluated for melanogenic activity.

RESULTS

Four patients (12.5%) of PUL had congenital lesions, and 24 (75.0%) had age of onset younger than 10 years. Confluency of lentiginous lesions (100%) and mild to moderate background interlesional hyperpigmentation (90.6%) were observed. The lentiginous lesions showed increased melanocytes, melanophages, basal melanins, lentiginous hyperplasia, and perivascular inflammatory cells compared with background interlesional hyperpigmentation, and PKC-βΙΙ was focally positive in 7 of 12 stained PUL lesions. Among the 16 patients who received laser treatments, 10 (62.5%) showed more than 50% of improvement.

CONCLUSIONS

The findings of this study will allow for improved diagnosis of PUL and understanding of its features, which may facilitate proper management in the future.

Synchronous melanomas arising within nevus spilus

Nevus spilus is a melanocytic cutaneous lesion consisting of a light brown background macule with numerous superimposed darker maculopapular speckles. Melanoma arising from a nevus spilus is rare, with less than 40 cases reported to date. The absolute risk for malignant transformation is not well defined, lacking a standardized management approach. We report a new case of melanoma arising from nevus spilus, with the additional peculiarity of multifocality. We offer our recommendations for the management of the condition.