Pigmented squamous cell carcinoma of the scrotum associated with a lentigo

Abstract

Only 13 cases of pigmented squamous cell carcinoma (SCC) have been reported in the English language literature, with most frequent development in the oral cavity and conjunctiva. However, no case of pigmented SCC of the scrotum has been reported. We report here a case of pigmented SCC that arose primarily in the scrotum of a 70-year-old man. Light microscopically, this tumour exhibited the typical features of a pigmented SCC, including not only keratinization and intercellular bridges but also colonization by plump dendritic melanocytes with marked pigmentation. These features were clearly confirmed by immunohistochemistry, including strong positivity of tumour cells for high-molecular-weight cytokeratin and of colonizing melanocytes for HMB-45. The tumour was associated with a lentiginous lesion and partly involved it. Melanocytes entrapped from the lentigo might therefore have been activated during enlargement of this tumour, resulting in melanocyte colonization. Fourteen cases of pigmented SCC, including ours, are clinicopathologically reviewed.

Pigmented Squamous Cell Carcinoma

“…9,10 Although pigmented squamous cell carcinomas (PSCC) have been reported in the cornea, conjunctiva, and oral mucosa, they are relatively rare in the skin, with only 17 reported cases, inclusive of the present one, in the English literature (Table 1). 1,[3][4][5]8,[12][13][14] The reported incidence of PSCC varies from 0.01% (5 cases of 46,791 invasive SCC examined) 8 to 7% 1 ; however, in the nonEnglish literature the incidence has been reported to be as high as 25%. 9,11 The difference in incidence may in part be due to the fact that the amount of pigment within the lesion is often sparse and may only be discernible by special techniques, or it may be race dependent.…”

“…9,11 The difference in incidence may in part be due to the fact that the amount of pigment within the lesion is often sparse and may only be discernible by special techniques, or it may be race dependent. 1,3,8,11,12 Furthermore, there are relatively few retrospective studies that have evaluated the actual incidence of pigment within various neoplasms. 1,2,8,15,16 Therefore, the true incidence of PSCC is difficult to ascertain.…”

“…The melanocytes in these lesions are cytologically benign, and it is hypothesized that their presence can be attributed to ''colonization'', rather than to a truly neoplastic process. [1][2][3][4][5][6][7] It is difficult to determine the actual incidence of this finding; because in general, benign neoplasms and non-melanocytic cutaneous malignancies are not reported to tumor registries. Moreover a pigmented modifier may not be incorporated into the coding system of many pathology reports for easy data retrieval.…”

Pigmented squamous cell carcinoma in situ of the conjunctiva

“…Other cases also reported had pigmented lesions near the tumor, such as racial melanosis [4], nevus [4,5], lentigo [6], and pigmented solar keratosis [5]. Pigmentation was theorized to have been acquired from an adjacent pigmented lesion [5,6].…”

Seltene und neu beschriebene histologische Varianten des kutanen Plattenepithelkarzinoms

“…Haut beschriebene, prominent mit intraepidermalen dendritischen Melanozyten versehene pigmentierte PE-CA [60] als auch proliferierende Trichilemmalzysten [76] …”