UV-irradiated melanocytic nevus simulating melanoma in situ

Background: An acral lentiginous melanoma in situ on the sole is often difficult to differentiate with the naked eye from an acquired plantar melanocytic nevus. Recent technical advances in epiluminescence microscopy have contributed to the differentiation of these two pigmented skin lesions. Objective: In this study, the correlation between dermatoscopic and histopathologic findings of acral lentiginous melanoma in situ on the sole are compared to those of acquired plantar melanocytic nevi. Methods: Three acral lentiginous melanomas in situ on the sole, and two cases of acral lentiginous melanoma were compared with 50 acquired plantar melanocytic nevi by means of dermatoscopy and histopathology. Results: The dermatoscopic surface profiles of acquired melanocytic nevi were composed of linear pigmentation accentuated mainly on the sulcus superficialis. Histologically, some areas of the sulcus superficialis corresponded to rete ridges of the epidermis, and nests of nevus cells were also often located there. In contrast, the acral lentiginous melanomas in situ showed diffuse, irregularly shaped pigmentation distributed in a disorderly fashion over the entire surface. Histologically, isolated areas of proliferation and small nest formations of atypical melanocytes were irregularly distributed in the epidermis. Conclusion: A distinctive dermatoscopic feature of acral lentiginous melanoma in situ is diffuse and irregular pigmentation over the entire surface of the lesion. This feature is helpful for differentiating acral lentiginous melanoma in situ from acquired plantar melanocytic nevi.

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Intracorneal Hematoma Showing Clinical and Dermoscopic Features of Acral Lentiginous Melanoma

Case Reports in Dermatological Medicine ◽

10.1155/2017/3509146 ◽

2017 ◽

Vol 2017 ◽

pp. 1-3

Author(s):

Ugur Uslu ◽

Franz Heppt ◽

Michael Erdmann

Keyword(s):

Correct Diagnosis ◽

Surgical Excision ◽

Skin Lesions ◽

Melanocytic Nevus ◽

Careful Examination ◽

Acral Lentiginous Melanoma ◽

Melanoma In Situ ◽

Malignant Skin ◽

Rule Out

Intra- and subcorneal hematoma, a skin alteration seen palmar and plantar after trauma or physical exercise, can be challenging to distinguish from in situ or invasive acral lentiginous melanoma. Thus, careful examination including dermoscopic and histologic assessment may be necessary to make the correct diagnosis. We here present a case of a 67-year-old healthy female patient who presented with a pigmented plantar skin alteration. Differential diagnoses included benign skin lesions, for example, hematoma or melanocytic nevus, and also acral lentiginous melanoma or melanoma in situ. Since clinical and dermoscopic examinations did not rule out a malignant skin lesion, surgical excision was performed and confirmed an intracorneal hematoma. In summary, without adequate physical trigger, it may be clinically and dermoscopically challenging to make the correct diagnosis in pigmented palmar and plantar skin alterations. Thus, biopsy or surgical excision of the skin alteration may be necessary to rule out melanoma.

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Sclerosing melanocytic lesions (sclerosing melanomas with nevoid features and sclerosing nevi with pseudomelanomatous features) – an analysis of 90 lesions

Radiology and Oncology ◽

10.2478/raon-2018-0003 ◽

2018 ◽

Vol 52 (2) ◽

pp. 220-228

Author(s):

Biljana Grcar-Kuzmanov ◽

Emanuela Bostjancic ◽

Juan Antonio Contreras Bandres ◽

Joze Pizem

Keyword(s):

Melanocytic Nevus ◽

Lymph Node Biopsy ◽

Female Age ◽

Melanoma In Situ ◽

Melanocytic Lesions ◽

Pagetoid Spread ◽

Mitotic Figures ◽

Age Range ◽

Diffuse Sclerosis

Abstract Background Sclerosing melanocytic lesions, which are characterized by either focal or diffuse sclerosis in the dermal component and atypical proliferation of predominantly nevoid melanocytes, remain poorly defined. Our aim was to analyze systematically their morphologic spectrum, especially the distinction between sclerosing melanocytic nevus and sclerosing melanoma, which has not been well documented. Patients and methods We collected 90 sclerosing melanocytic lesions, occurring in 82 patients (49 male, 33 female; age range from 21 to 89 years). A four probe fluorescent in situ hybridization (FISH) assay was performed in 41 lesions to substantiate the diagnosis of sclerosing melanomas. Results A prominent full-thickness pagetoid spread of melanocytes was identified in 44 (48%) lesions, and a melanoma in situ adjacent to the sclerosis in 55 (61%) lesions. In the intrasclerotic component, maturation was absent in 40 (44%) and mitotic figures were identified in 18 (20%) lesions. Of the 90 lesions, 26 (29%) were diagnosed morphologically as nevi and 64 (71%) as melanomas (Breslow thickness from 0.4 to 1.8 mm), including 45 (50%) melanomas with an adjacent nevus. A four-probe FISH assay was positive in the sclerotic component in 14 of 25 lesions diagnosed morphologically as melanomas and none of 16 nevi. A sentinel lymph node biopsy was performed for 17 lesions and was negative in all cases. Conclusions Sclerosing melanocytic lesions form a morphologic spectrum and include both nevi and melanomas. The pathogenesis of sclerosis remains obscure but seems to be induced by melanocytes or an unusual host response in at least a subset of lesions.

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