A squamous cell carcinoma arising from scrotal epidermal cyst. A case report and review of 94 cases from the world literature

Abstract

Epidermal cysts are a common benign skin abnormality, comprising 85-90% of all excised skin cysts. The term epidermal inclusion cyst refers specifically when the cyst resulted from the implantation of epidermal elements in the dermis. Squamous cell carcinomas (SCCs) are common skin lesions; however, a malignant transformation of an epidermal cyst is very rare with incidence of 0.011-0.045%. Few cases of malignant transformation of an epidermal cyst have been reported in the literature so far. This paper presents a case of squamous cell carcinoma arising from a scrotal epidermal cyst.

Squamous cell carcinoma arising in an epidermal cyst of urinary bladder associated with vesicolithiasis: A case report and review of the literature

“…The presence of keratinized material in the urine sample suggests an epidermoid cyst in the urinary tract [5] . ECs are usually benign, however, a few cases with MT have been reported in the literature with a reported rate up to 0.045% [1] , [8] , [9] . SqCC arising in an EC is rarely suspected in routine clinical practice.…”

“…In a long-standing EC, the MT can occur suddenly with some abnormal changes in the cyst including; a firm mass replacing the cyst, increase in size, discharge, pain, ulceration and bleeding inside the cyst which do not response to conservative treatment [7] , [10] , [12] . In a series of 94 cases of SqCC arising in EC reported, the most common site were head and neck (55%) followed by lower limb (13%), trunk (13%), perineum (8%) and upper limb (6%) with a slightly males' predominance (65%) [1] . Another review of 19 cases of SqCC arising in EC showed that majority of those cases were in males and the age ranged from 20 to 80 years old with mean age of 43.2 years [13] .…”

“…Age of our patient was 40-year-old and uniquely occurred in urinary bladder. Other than skin, malignancy arising from EC also occur in internal organs such as kidney, ureters, testes, intra-cranial regions and ovaries with extremely low occurrence rate [1] . A proper treatment for EC with MT is surgical excision, however, metastasis or local invasion of the tumor will demand additional therapeutic protocols including; disease palliative systemic chemotherapy or immunotherapy with PD-1 blockade using cemiplimab [12] .…”

“…Epidermal cyst (EC), also known as sebaceous cyst, is the most common cyst of the skin [1] , which is characterized by keratinized stratified squamous epithelium with distinct granular layer producing lamellated keratin and sebaceous material without calcification [2] , [3] . ECs are more frequent in males than females [4] and can occur at any age and any part of the body, however, they are usually present in the hair-bearing areas such as the scalp, face, neck, trunk, and back regions [3] , [4] , [5] .…”

“…ECs can rarely transform into malignant neoplasms such as squamous cell carcinoma (SqCC) and basal cell carcinoma. According to the literature, the most frequent sites for ECs transforming into SqCCs are head and neck [1] . Here we present probably the first case of an EC arising in the urinary bladder (UB) which is associated with vesicolithiasis and malignant transformation (MT) into SqCC.…”