Proliferations of the epidermoid cyst wall

Malignant Transformation in a Typical Epidermal Cutaneous Cyst

“…It has however been described on several occasions, in the form of Bowen's disease, Paget's disease, Bowenoid papulosis, mycosis fungoides, Merkel cell carcinoma, basal and squamous cell carcinoma [2][3][4][5][6][7][8][9]. To date, nineteen well-documented cases of malignant transformation into squamous cell carcinoma have been reported in the walls of epidermal cysts, with an incidence ranging between 0.011 and 0.045% [4,13,14].…”

“…As such, they are thought to be derived from, or mimic to, the infundibular portion of the hair follicle [1]. Malignant transformation of these cysts are known to occur, although only rarely and includes basal and squamous cell carcinoma [2][3][4], Paget's disease [2], Bowen's disease [5], mycosis fungoides [6,7], Merkel cell carcinoma [8] and malignant melanoma [9]. It is worth mentioning, however, that among the several publications reporting on malignant transformation of an epidermal cyst, those that are relating to squamous cell carcinoma and are well documented, have an incidence between 0.011-0.045% [4,[10][11][12][13][14].…”

Dermal cysts: a dermatopathological perspective and histological reappraisal

“…They most commonly arise in the mid‐ to lower dermis and do not shell out easily at removal. Morphological variants such as sprouting appendages arising from the main cyst, tuber‐shaped cysts and gigantic (up to 17 × 20 cm) cysts have been reported in the literature, 2 as well as concomitant conditions such as Bowen’s disease, Paget’s disease and nevi 3 . Although rare, occurrences of Merkel cell carcinoma, 3 basal cell carcinoma 4 and squamous cell carcinoma 5 have been reported in conjunction with infundibular cysts.…”

“…Two distinct but rare types of infundibular cyst are associated with human papillomavirus (HPV) infection. The first type reported can be found on pressure points of the plantar surface of the foot 3 and is associated most commonly with HPV serotype 60 8 . Multiple lesions are rarely seen.…”

Melanoma In Situ Involving an Epidermal Inclusion (Infundibular) Cyst

“…1 Histopathologically, epidermal inclusion cysts are lined by stratified squamous epithelia containing a granular layer with basketweave to laminated stratum corneum. These cysts are commonly found on the face, back, or chest.…”