Proliferating trichilemmal cyst

Abstract

Fourteen cases (9 female, 5 male) of proliferating trichilemmal cysts are reported. The patients age-range was 40-80, 12 being over 60. The cysts wee present for 2-50 years and enlarged in the months or years before the observation. Seven were ulcerated. In 4 with multiple lesions both proliferating and ordinary trichilemmal cysts were present. The histological features were typical in all but one patient (evolution towards squamous cell carcinoma?) with some variation from lesion to lesion and from area to area in the same tumour. The microscopic features suggest that the proliferating trichilemmal cyst must be considered an hamartoma of the terminal hair follicle, not only related to the isthmic segment of the outer root sheath but with some differentiation (smaller and more variable) towards the infundibular and matricial segments. The tumour is likely to be a proliferating trichilemmal cyst from the beginning and not a peculiar evolution of an ordinary, pre-existant, trichilemmal cyst.

Peri-Genital Proliferating Trichilemmal Cyst: A Clue to Underlying Malignancy

“…[2] a b PTC is thought to originate from the trichilemmal cyst (TC) following some trauma and inflammation. [1,3] PTC's can occur de novo. Although PTC is considered biologically benign, they may be locally aggressive with potential of recurrences and malignant transformation with metastasis to lymph nodes and internal organs.…”

“…PTC's tend to occur after the age of 60years [5] but they have been reported in individuals as young as 18 years. [6] Uncommonly present with ulcerated, fungating growth [1] and at atypical sites like neck, trunk, groin, mons-pubis, vulva, and gluteal region; the upper and lower extremities, including the elbow, the dorsum of the hand, and the index finger; the face, including the forehead, nose, eyelid, lip, and intraoral; and even the base of the skull. [2] a b PTC is thought to originate from the trichilemmal cyst (TC) following some trauma and inflammation.…”

“…[1] PTC is an rare tumour originating from the outer root sheath of hair follicle. It is thought to arise from trichilemmal cyst with histological hallmark of trichilemmal keratinisation.…”

Proliferating trichilemmal tumor of scalp

“…[6] It is not certain that PTT develops de novo or arises from a pre-existing cyst. [7] The effects of trauma or inflammation was considered to be the cause of the presence of a pre-existing pilar cyst. [6] The human papilloma virus was presented in some cases.…”

Squamous Cell Carcinoma of the Scalp Masquerading as Trichilemmal Tumor of the Scalp

“…22 Here, adjuvant therapy was not used and the outcome was variable, which led for a possible role of adjuvant radio therapy or chemotherapy to improve disease-free survival. 6 Ye et al reported 50% recurrence in MPTT within 2 to 14 months where none had been given adjuvant therapy.…”