Factors Affecting Sentinel Node Metastasis in Thin (T1) Cutaneous Melanomas: Development and External Validation of a Predictive Nomogram

PURPOSE Thin melanomas (T1; ≤ 1 mm) constitute 70% of newly diagnosed cutaneous melanomas. Regional node metastasis determined by sentinel node biopsy (SNB) is an important prognostic factor for T1 melanoma. However, current melanoma guidelines do not provide clear indications on when to perform SNB in T1 disease and stress an individualized approach to SNB that considers all clinicopathologic risk factors. We aimed to identify determinants of sentinel node (SN) status for incorporation into an externally validated nomogram to better select patients with T1 disease for SNB. PATIENTS AND METHODS The development cohort comprised 3,666 patients with T1 disease consecutively treated at the Istituto Nazionale Tumori (Milan, Italy) between 2001 and 2018; 4,227 patients with T1 disease treated at 13 other European centers over the same period formed the validation cohort. A random forest procedure was applied to the development data set to select characteristics associated with SN status for inclusion in a multiple binary logistic model from which a nomogram was elaborated. Decision curve analyses assessed the clinical utility of the nomogram. RESULTS Of patients in the development cohort, 1,635 underwent SNB; 108 patients (6.6%) were SN positive. By univariable analysis, age, growth phase, Breslow thickness, ulceration, mitotic rate, regression, and lymphovascular invasion were significantly associated with SN status. The random forest procedure selected 6 variables (not growth phase) for inclusion in the logistic model and nomogram. The nomogram proved well calibrated and had good discriminative ability in both cohorts. Decision curve analyses revealed the superior net benefit of the nomogram compared with each individual variable included in it as well as with variables suggested by current guidelines. CONCLUSION We propose the nomogram as a decision aid in all patients with T1 melanoma being considered for SNB

Verrucous hemangioma with angiokeratoma-like features

Verrucous hemangioma (VH) is a rare vascular malformation showing characteristic clinico-pathologic features. Since its formal individualization in 1967, little has been written on this entity. Here we report a case of extensive VH involving the whole length of the right lower limb of a 39-year old man. Clinically it consisted of numerous bluish-red, well-demarcated plaques and nodules with keratotic surface arranged in a linear fashion. On the lower third of the leg also an irregular shaped ulcer with red base and prominent definite borders was present. Differential diagnosis included angiokeratoma circumscriptum neviforme (ACN) and Cobb-Syndrome mainly; also lymphangioma circumscriptum and angioma serpiginosum were considered. Histologic findings revealed hyperkeratosis, acanthosis and papillomatosis in the epidermis. In the superficial and reticular dermis and partly in the subcutaneous tissue vascular dilatation and proliferation were observed. Finally, immunohistochemical findings of endothelial cells staining with factor VIII-related antigen and CD 34, confirmed the vascular nature of the lesion

Neurofibromatosi segmentaria. Descrizione di due casi e revisione della letteratura

Two cases of segmental neurofibromatosis (SNF) in a 57-year old woman and in a 52-year old man are reported. Both patients presented linear, exophytic, cutaneous lesions located on the left lumbar and left pectoral regions respectively, dating from 15-20 years. The family history was negative for skin and neurological diseases. Examination revealed multiple, firm, smooth surfaced, skin-colored papules arranged in a linear fashion. Café-au-lait macules, axillary freckling and Lisch nodules were absent. Two papules were surgically excised. Histopathological evaluation showed the features of not encapsulated neurofibromas. In both patients, neurological and ophthalmological investigations were within normal limits. Segmental neurofibromatosis is a rare disorder characterized by the presence of cutaneous neurofibromas with or without café-au-lait macules arranged in linear fashion along one or several dermatomes. This disorder accounts for about 10% of cases of neurofibromatosis. In 93% of cases the patients with SNF have a negative family history of neurofibromatosis, in keeping with the pathogenesis of it (somatic mutation). The incidence of malignant transformation is less then 5% and it seems related with the inactivation of NF1 gene. It is mandatory for the patients with SNF to have an accurate information about their disease as well as a life period of follow-up