Transformation of Seborrheic Keratosis into Bowenoid Actinic Keratosis via Three Steps of Histological Change in a Patient with Rheumatoid Arthritis Treated with Multiple Immunosuppressants

Abstract

We report a case of seborrheic keratosis (SK) that transformed into bowenoid actinic keratosis (AK) via three steps of histological change in a 77-year-old woman. The patient presented with a multiple-year history of a brownish lesion on the right cheek. She reported that some months earlier she had noted a pinkish lesion developing within the brownish lesion. She had also been treated with several immunosuppressants for rheumatoid arthritis for many years. Physical examination revealed a nodule measuring 13 × 12 mm on the lateral side of the right upper cheek. The lesion comprised three regions: a brownish hyperkeratotic region in the upper portion; a pinkish region in the lower portion; and a slightly dented, band-like region between the other two regions. Histopathologically, the specimen consisted of four zones: SK comprising basaloid cells; SK composed of squamoid cells; atrophic AK; and bowenoid AK. The zones of SK with basaloid cells and squamoid cells clinically corresponded to the brownish hyperkeratotic region. Atrophic and bowenoid AK zones corresponded to the dented, band-like region Case Oka et al.: Transformation of Seborrheic Keratosis 20and pinkish region, respectively. Collectively, the nodular skin lesion was diagnosed as SK associated with atrophic and bowenoid AK within the SK lesion. The present case suggests that bowenoid AK developed from SK by malignant transformation via three steps of histological change. The facts that our patient had received treatment with several immunosuppressants and that no other AK lesions were evident around the AK support the notion that in this case, bowenoid AK developed from SK by malignant transformation.

Seborrheic Keratosis With Malignant Transformation (Invasive or Noninvasive Squamous Cell Carcinoma Arising in Seborrheic Keratosis): A Clinicopathologic and Immunohistochemical Study of 11 Cases

“…Previous studies have also reported invasive or noninvasive squamous cell carcinoma arising in seborrheic keratosis. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] In addition, porocarcinoma has rarely been reported as a combined tumor with seborrheic keratosis. [30][31][32][33][34] However, 2 of these studies did not contain histopathological images.…”

“…However, a few cases of squamous cell carcinoma arising from seborrheic keratosis [10][11][12][13][14][15][16][17][18][19][20] and seborrheic keratosis with bowenoid transformation [21][22][23][24][25][26][27][28][29] have been reported. In such a case, a transition between seborrheic keratosis and squamous cell carcinoma, both of which are on an identical group of keratinocytic neoplasms, can be observed.…”

“…However, most previous cases of squamous cell carcinoma arising from seborrheic keratosis have been reported in a single case report. 10,11,13,14,[17][18][19][21][22][23][24]26,29 Other cases have been reported in case series, but these studies did not include a detailed histopathological and immunohistochemical analysis. 12,15,16,20,25 Therefore, little is known about the pathological characteristics of seborrheic keratosis with malignant transformation.…”