Giant congenital cellular blue naevus of the scalp with disseminated common blue naevi of the body

Melanoma on congenital melanocytic nevi

Among nevus-associated melanomas, which overall account for 20%-30% of all melanomas, those arising specifically in congenital melanocytic nevi are infrequent, but can be disproportionately frequent in childhood and adolescence. Congenital melanocytic nevi (CMNi) are common benign melanocytic tumors that are present at birth or become apparent in early childhood. They are classified based on the projected adult size. Small and medium-sized CMNi are frequent, whereas large/giant CMNi (over 20 cm in diameter) are rare, but can be associated with high morbidity due to marked aesthetic impairment and the risk of neurocutaneous syndrome or melanoma development. In this setting, melanomas can appear in early childhood and are very aggressive, while the risk of small-medium CMNi of developing melanoma is low and similar to non-congenital melanocytic nevi. Histologically, most melanomas on CMNi initiate their growth at the epidermal-dermal junction, but in large/giant CMNi they can develop entirely in the dermis, in deeper tissues, or in extracutaneous sites (especially in the central nervous system). Most CMNi harbour an NRAS mutation, but other genes are rarely involved, and gene translocations have recently been described. However, no prognostic implications have been associated with the CMN genotype. Melanomas developed on CMNi harbour additional molecular alterations to which the aggressive clinical course of these tumors has been attributed. This review covers the distinctive clinical and pathological aspects of melanomas on CMNi, and includes the epidemiology, etiopathogenesis, clinical and dermoscopic presentation, histological and molecular characteristics, as well as tumour behaviour.

Giant Congenital Blue Nevus Presenting as Cutis Verticis Gyrata: A Case Report and Review of the Literature

OBJECTIVES

Cerebriform intradermal nevus and giant congenital blue nevi are rarely reported melanocytic nevi with clinical and histopathologic similarities. Both are known to produce cutis verticis gyrata. We report a significantly large occipital scalp congenital blue nevus with secondary cutis verticis gyrata. The aim of this report is to increase clinical awareness of this entity, highlight histopathologic and mutational features of cerebriform intradermal nevi and giant congenital blue nevi, and stress the importance of clinicopathologic correlation for diagnosis.

METHODS

Case report and review of the literature.

RESULTS

A 20-year-old Asian male presented with a long-standing, large (20 cm × 30 cm), exophytic tumor at the occipital scalp and posterior neck. The skin overlying the lesion was arranged in thick folds resembling the surface of the brain, devoid of hair follicles, and discolored by salt-and-pepper pattern hyperpigmentation. After correlating the clinical and histopathologic findings, we diagnosed giant congenital blue nevus with secondary cutis verticis gyrata. Staged surgical excision was performed with subsequent treatment for hypertrophic scarring and occipital alopecia.

CONCLUSIONS

Cerebriform intradermal nevus and giant congenital blue nevus have overlapping histologic and clinical features. Head and neck surgeons should be aware that nomenclature of these tumors is subjective and often imprecise. Diagnosis requires correlation of clinical findings, patient history, and histopathology. Surgical excision is advised due to rare malignant transformation potential.

[Developmental abnormalities and nevi of the scalp]

Unusual congenital or early-onset skin lesions on the scalp often pose a diagnostic challenge particularly as the clinical evaluation may be hampered by dense hair growth. Thus, this paper provides a concise review on developmental abnormalities and nevi with exclusive or predominant scalp localization. Aplasia cutis congenita occurs as an isolated finding, in association with genetic syndromes, nevi and anomalies or as a consequence of intrauterine trauma and teratogens. A hairless area with a narrow surrounding rim of hypertrichosis (hair collar sign) may point to occult cranial dysraphism, especially if accompanied by further suggestive signs as port-wine stains, large hemangiomas, dimples, congenital dermoid cysts, and sinuses. Many diverse entities may hide behind cutis verticis gyrata with the primary essential form being rare and representing a diagnosis of exclusion. In contrast to former belief, benign adnexal tumors arise in a nevus sebaceus considerably more often than basal cell carcinomas and other malignant epithelial tumors. Provided that tumor development is not suspected, excision of a nevus sebaceus nevus is indicated primarily for aesthetic-psychosocial reasons. However, surgical treatment is considerably easier in small children. Nevus sebaceus may be a cutaneous marker for several complex syndromes whereas nevus psiloliparus presents almost always in connection with encephalocraniocutaneous lipomatosis. Congenital melanocytic nevi of the scalp tend toward clinical regression, so that surgical intervention in large lesions should be carefully considered. In contrast, the threshold for excision of blue nevi and other conspicuous melanocytic nevi on the scalp should be low, especially since they are difficult to monitor.

Congenital melanocytic nevi-when to worry and how to treat: Facts and controversies

Congenital melanocytic nevi (CMN) are evident in 1% to 6% of neonates. In some studies, nevi with clinical, dermatoscopic, and histologic features identical to CMN have had a prevalence of more than 15% in older children and adults, possibly reflecting the "tardive" appearance of nevi programmed from birth. There is ongoing debate about the magnitude of the risk of melanoma and other complications associated with CMN of various sizes and the best approach to management of these lesions. We review the natural history of CMN, including proliferative nodules and erosions during infancy, neurotization, and spontaneous regression, and features of variants such as speckled lentiginous and congenital blue nevi. The risk of melanoma arising within small-sized (<1.5 cm) and medium-sized CMN is low (likely <1% over a lifetime) and virtually nonexistent before puberty. Recent data suggest that melanoma (cutaneous or extracutaneous) develops in approximately 5% of patients with a large (>20 cm) CMN, with about half of this risk in the first few years of life. Melanoma and neurocutaneous melanocytosis (NCM) are most likely in patients with CMN that have a final size of >40 cm in diameter, numerous satellite nevi, and a truncal location. One-third of individuals with NCM have multiple medium-sized (but no large) CMN. In patients at risk for NCM, a screening gadolinium-enhanced magnetic resonance imaging, preferably before age 6 months, and longitudinal neurologic assessment are recommended. Management of CMN depends on such factors as the ease of monitoring (more difficult for large, dark, thick nevi) and cosmetic and psychologic benefits of excision or other procedures. CMN require lifelong follow-up. Periodic total body skin examinations are necessary for all patients with large CMN, even when complete resection (often impossible) has been attempted.