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Year : 2016  |  Volume : 64  |  Issue : 2  |  Page : 357--358

Giant trichilemmal cyst of the scalp

Lee A Tan, Aparna Harbhajanka, Manish K Kasliwal, Sukriti Nag, Lorenzo F Munoz 
 Department of Neurosurgery and Pathology, Rush University Medical Center, Chicago, Illinois, USA

Correspondence Address:
Manish K Kasliwal
Department of Neurosurgery, Rush University Medical Center, Suite 855, Chicago - 60612, Illinois

How to cite this article:
Tan LA, Harbhajanka A, Kasliwal MK, Nag S, Munoz LF. Giant trichilemmal cyst of the scalp.Neurol India 2016;64:357-358

How to cite this URL:
Tan LA, Harbhajanka A, Kasliwal MK, Nag S, Munoz LF. Giant trichilemmal cyst of the scalp. Neurol India [serial online] 2016 [cited 2021 Jan 22 ];64:357-358
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Full Text

A 66-year-old man with a significant previous medical history of type 2 diabetes mellitus and end-stage renal disease (on hemodialysis) presented with an enlarging scalp mass measuring 7.4 × 5.0 × 4.0 cm that, as per history, had doubled in size over the past year. It was causing increasing discomfort [Figure 1]a. His physical examination was otherwise unremarkable. Magnetic resonance imaging demonstrated a mass that was hyperintense on both T1- and T2-weighted imaging [Figure 1]b and [Figure 1]c. Given the continued growth in size of the lesion and the need for a tissue diagnosis, the patient was taken to the operative room and underwent complete excision of the scalp mass without any complications. The histopathological examination revealed a cyst lined by stratified squamous epithelium with a lack of granular layer, confirming the diagnosis of a trichilemmal cyst [Figure 1]d and [Figure 1]e. The patient was discharged in stable condition and was doing well at the 6-month follow-up visit, without recurrence of the scalp mass.{Figure 1}

Trichilemmal cysts (TCs), also known as pilar cysts, are rare, benign, keratin-filled skin neoplasms that arise from the outer root sheath of the hair follicles.[1] These cysts can affect up to 10% of the population, with the scalp being involved in more than 90% of cases. The average age of onset is at 60 years, with a slight female predilection.[2] Other more aggressive forms, such as proliferating trichilemmal tumors (PTT) and malignant proliferating trichilemmal tumors (MPTTs), can also occur, but they are much less common.[1],[3] PTTs are believed to originate from pre-existing TCs owing to subsequent inflammation or trauma. The complete loss of p53 tumor suppressor gene activity is believed to be responsible for transformation of PTT to MPTT.[1],[3]

TCs typically present as round, smooth, painless scalp masses of varying sizes. Although this lesion is usually solitary, multiple lesions in the same patient have been reported in literature.[1] The differential diagnosis for a TC may include epidermoid cyst, lipoma, keratoacanthoma, dermatofibrosarcoma protuberans, and primary cranial vault lymphoma. The characteristic histological feature of TCs is the presence of trichilemmal keratinization, where there is an abrupt transition from the nucleated epithelial cells to the anucleate, keratinized cells without the granular layer.[1] The more aggressive PTTs share this histological feature, but are usually larger and have a more atypical appearance that often can mimic squamous cell carcinoma. MTTs are very rare, and have an invasive component along with the classical appearance of trichilemmal keratinization.[3] Surgical resection of TCs is the treatment of choice and is often curative. The more aggressive PTTs may require wide local excision and have a higher risk of recurrence. If MTT is encountered, additional measures such as lymph node dissection, chemotherapy, and radiation may be needed in addition to complete local resection.

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1Satyaprakash AK, Sheehan DJ, Sangüeza OP. Proliferating trichilemmal tumors: A review of the literature. Dermatol Surg 2007;33:1102-8.
2Chang EF, Raygor KP, Berger MS. Contemporary model of language organization: An overview for neurosurgeons. J Neurosurg 2015;122:250-61.
3Khaled A, Kourda M, Fazaa B, Kourda J, Ben Jilani S, Kamoun MR, et al. Malignant proliferating trichilemmal cyst of the scalp: Histological aspects and nosology. Pathologica 2011;103:73-6.