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Int J Clin Exp Pathol 2012;5(5):455-457

Case Report
Seborrheic inclusion cyst of the skin positive for cytoplasmic inclusion bodies and HPV

Tadashi Terada

Department of Pathology, Shizuoka City Shimizu Hospital, Shizuoka, Japan

Received February 27, 2012; accepted April 25, 2012; Epub May 23, 2012; Published June 30, 2012

Abstract: Seborrheic inclusion cyst (SIC) is a very rare variant of epidermal cyst of the skin. SIC shows seborrheic keratosis (SK)-like lesion in
epidermal cyst. SIC is extremely rare; only 6 case reports have been published in the English literature. However, no immunohistiochemical
study of SIC has been reported. A 41-year-old Japanese man noticed a subcutaneous tumor in the neck. Physical examination showed slightly
mobile tumor in the subcutaneous tissue, and total excision was performed. Grossly, the tumor (1 x 1 x 0.8 cm) was cyst containing
atheromatous keratin. Microscopically, the lesion is a cyst containing keratins. About one half of the cyst showed features of epidermal cyst
consisting of mature squamous epithelium with granular layers. The other one half showed SK-like epidermal proliferation. The SK-like area
showed basaloid cell proliferation with pseudohorn cysts. No significant atypia was noted. Many eosinophilic cytoplasmic inclusion bodies
were noted in the SK-like area. Immunohistochemically, the SK-like area was positive for pancytokeratin AE1/3, pancytokeratin CAM5.2, p63,
and Ki-67 (labeling=8%) and HPV, but negative for p53. The pathological diagnosis was SIC. (IJCEP1202013)

Keywords: Seborrheic inclusion cyst, epidermal cyst, cutaneous pathology, immunohistochemistry, HPV

Address all correspondence to:
Dr. Tadashi Terada
Department of Pathology
Shizuoka City Shimizu Hospital
Miyakami 1231 Shimizu-Ku
Shizuoka 424-8636, Japan.
Tel: 81-54-336-1111; Fax: 81-54-336-1315
E-mail: piyo0111jp@yahoo.co.jp