Agminated spitz nevus on sole of elderly.

Sir,

Spitz nevus (SN) is an acquired, benign, melanocytic neoplasm found predominantly in children and adolescents; commonly appears as a solitary, dome-shaped, firm, red or brown nodule located most commonly over the face or leg. Multiple grouped (agminated) SN are much less frequent[1] and its occurrence over sole has been rarely reported.[2] We report a case of 60-year-old female patient who visited us with an asymptomatic lesion on her right sole of 1-year duration. On examination, there were three, black to grey colored, closely grouped, firm ellipsoid raised plaques, coalescing to give an impression of a single plaque of 4 cm × 5 cm, with irregular edges showing diffusion of pigment over sole [Figure 1]. The lesion closely resembled an acral melanoma. Skin biopsy showed well-circumscribed, vertically oriented nests of epithelioid and spindle shaped cells with abundant cytoplasm containing fine dispersed melanin pigment and large nucleus with regular nuclear contour. Within the nest were eosinophilic globules (“Kamino bodies”) [Figure 2a and b]. No mitoses were seen. There was maturation with depth in the dermis and no subcutaneous spread.

Figure 1

Three black to grey, closely grouped plaques with diffusion of pigment at margin. A 3-mm sized red erosion on posteromedial aspect (arrow) represents the site of skin biopsy

Figure 2

(a) Photomicrograph showing vertically oriented nests of epithelioid and spindle shaped cells with clefting at margins. Homogenous eosinophilic globule (arrow) represents “Kamino body” (H and E, ×20) (b) (Inset for a): Nevus cells showing abundant cytoplasm containing fine dispersed melanin pigment, and large nucleus with regular nuclear contour without any mitosis (H and E, ×100)

The SN, also known as “benign juvenile melanoma,” was originally thought to occur mainly in children with a ratio of spitz nevi to melanoma reported as greater than 60:1 in individuals younger than 20 years, whereas the ratio gets completely reversed to less than 1:60 after 50 years.[3] In adult onset cases of SN, involvement of extremities including dorsal surface of hands and feet are common, but lesions on glabrous skin of soles are reportedly uncommon with only four cases in world's literature.[2456] Of these, only one had age of onset in 6th decade, i.e., 68 years.[3] We add the 2nd case to the list of SN over sole of elderly.

SN usually presents as a solitary lesion; however, cases with multiple SN have been reported. Multiple SN is divided into two subgroups: Grouped (agminated) or disseminated SN. About forty cases of agminated SN have been reported in literature[1] with only one report on the sole of a 12-years-old African-American girl.[2] However, in our opinion, based on review of the clinical photograph, the above mentioned case may be better described as “localized multiple SN” as three lesions were seen widely distributed over sole; whereas in our patient three lesions were closely grouped together, thus representing true agminated lesion over sole. More than 50% of multiple SN occurs in patients under 5 years, and the most frequent site is the face, followed by the arms. Therefore, we report the most unusual case of multiple agminated SN over sole of an elderly from Asia.

Moreover, 90% of SN is less than 1 cm in size. To the best of our knowledge, there are only two reports of benign SN with an agminated area larger[17] than that of our case (4 cm × 5 cm). However, those cases had involvement of lumber region and cheek respectively. Our case is the largest agminated plaque on sole. Pigmented SN share several clinical and histologic features with spitzoid melanoma (SM) and therefore makes the distinction between the two entities difficult at times. Both are characterized by nests of atypical melanocytes within the epidermis and dermis. However, various features favouring the diagnosis of SN over a SM are: Low mitotic activity with regular nuclei of similar size and rarity of large nucleoli, uniform melanocytic nests oriented perpendicular to skin surface, files of single cells dispersed between reticular dermal collagen bundles, presence of Kamino bodies, clefts between intraepidermal melanocytic nests from keratinocytes, presence of maturation especially deep within the lesion and absence of involvement of subcutaneous fat.[89]

We conclude that the awareness of SN in adults and its possible atypical presentations are important to differentiate it from malignant melanoma and prevent excessive and mutilating surgery on mechanically important sites.