A cellular blue nevus with pigmented epithelioid melanocytoma‐like pattern on the ipsilateral upper arm associated with a congenital plaque‐type blue nevus on the hand

Abstract

A 36‐year‐old man presented with a subcutaneous nodule on the right upper arm. A small nodule had developed 8 years earlier, and grew in size, accompanied by a tingling sensation and numbness. In addition, he had a bluish irregular patch on the right hand since birth, which crossed from the palm to the dorsal hand. Skin biopsies from the hand showed a heavily pigmented melanocyte proliferation in the dermis with perieccrine, perivascular, and perineural involvement, and a diagnosis of congenital plaque‐type blue nevus was made. The tumor on the arm was located closely along the median nerve, and was observed as a large black pedunculated round tumor. Histopathologically, the tumor on the arm consisted of densely packed tissue with nevoid cells without atypia in the larger nodular part, and heavily pigmented spindle and epithelioid melanocytes in the slender stalk area, which was diagnosed as cellular blue nevus with pigmented epithelioid melanocytoma‐like pattern. Next‐generation sequencing revealed GNAQ mutations in the hand lesion, and in the lesions on the arm. This case suggests that the areas of skin following the same neural distribution of a congenital plaque‐type blue nevus on the extremities should be followed up for secondary changes.

Large Plaque-type Blue Nevus with GNAQ Q209P Mutation, Involving Mammary Gland Tissue: Under-Recognized Mammary Condition as an Origin of Primary Mammary Melanocytic Tumors

“…23 All 4 literature cases of plaque-type blue nevus tested by DNA sequencing harbored the GNAQ Q209P mutation. 3,11,25 In addition, extensive dermal melanocytoses, including nevus of Ota and nevus of Ito, also have the GNAQ Q209P mutation. [4][5][6] Therefore, mosaicism of the GNAQ Q209P mutation would be a characteristic or specific genetic alteration in extensive melanocytoses, including plaque-type blue nevus.…”

Malignant melanoma associated with a plaque-type blue nevus of the cheek: a case report

“…To our knowledge, this is the first reported case of malignant melanoma associated with PTBN in the cheek. The early surgical removal of such a nevus should be considered when subcutaneous nodules develop, owing to their potential for malignant transformation [ 18 , 19 ]. Long-term monitoring is required regardless of whether surgery is conducted.…”

Role of miRNAs in melanin metabolism: Implications in melanin‐related diseases

“…[59][60][61] The increase in the number of melanocytes is the pathophysiological basis of pigmented nevus and cafe-au-lait-spots. 62,63 Conversely, the decrease in the number of melanocytes and the decreased function of the enzymes related to melanin metabolism can easily lead to the occurrence of vitiligo. miRNAs may regulate the viability, melanogenesis, and metabolism of melanocytes through multiple targets and participate in the process of melanin metabolism diseases.…”

“…UV rays and endocrine disorders induce increased TYR activity and melanin transfer, abnormal melanocyte activity, and prone to chloasma and skin melanoma 59‐61 . The increase in the number of melanocytes is the pathophysiological basis of pigmented nevus and cafe‐au‐lait‐spots 62,63 . Conversely, the decrease in the number of melanocytes and the decreased function of the enzymes related to melanin metabolism can easily lead to the occurrence of vitiligo.…”