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  Table of Contents    
Year : 2014  |  Volume : 57  |  Issue : 4  |  Page : 646-647
Malignant proliferating trichilemmal tumor of the scalp masquerading as squamous cell carcinoma: A need for common awareness

1 Department of Oncopathology, Delhi State Cancer Institute, Dilshad Garden, New Delhi, India
2 Department of Radiotherapy, Delhi State Cancer Institute, Dilshad Garden, New Delhi, India

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Date of Web Publication11-Oct-2014

How to cite this article:
Tikku G, Jain D, Grover R. Malignant proliferating trichilemmal tumor of the scalp masquerading as squamous cell carcinoma: A need for common awareness. Indian J Pathol Microbiol 2014;57:646-7

How to cite this URL:
Tikku G, Jain D, Grover R. Malignant proliferating trichilemmal tumor of the scalp masquerading as squamous cell carcinoma: A need for common awareness. Indian J Pathol Microbiol [serial online] 2014 [cited 2023 Nov 30];57:646-7. Available from:


A 63-year-old male, presented to a referral oncology center postoperatively for further management of squamous cell carcinoma (SCC) of the scalp. There were multiple gradually increasing scalp masses for the last 4-5 years and the patient had been keeping long hair since birth. In the first surgery, a large fungating mass measuring 7.5 cm 7.5 cm 5 cm in the left occipital region was excised and diagnosed as an SCC. A subsequent completion surgery had the same diagnosis for the largest scalp swelling measuring 4 cm 3 cm 2 cm in right occipital region.

The histopathology review revealed an infiltrating dermal tumor, in the form of nests and lobules of pleomorphic keratinizing epithelial cells, with abrupt trichilemmal keratinization [Figure 1]a. Few clear cells indicating trichilemmal origin were also noted [Figure 1]b. A review diagnosis of malignant proliferating trichilemmal tumor (MPTT) was rendered.
Figure 1: (a) Cytologic atypia and nuclear anaplasia in malignant proliferating trichilemmal tumor of the scalp mimicking a squamous cell carcinoma, (b) Lobules composed of clear cells with prominent nucleoli in malignant proliferating trichilemmal tumor simulating a trichilemmal carcinoma, (c) Microinvasive tumor arising in a proliferating trichilemmal tumor (a-c, H and E ×40), (d) Benign trichilemmal cyst of the scalp (H and E ×10)

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Sections from the right occipital swelling of the second surgery showed dermal epithelial neoplasm without significant nuclear atypia/mitosis except for few tongues of pleomorphic keratinizing cells. Diagnosis of microinvasive tumor arising in a proliferating trichilemmal tumor (PTT) was formulated [Figure 1]c. Smaller cysts excised showed histology of benign trichilemmal cysts (TC) [Figure 1]d.

Whole body PET scan did not show any residual/metastatic disease. Patient is on follow-up and free of disease 18 months postoperatively with no adjuvant therapy been administered.

Proliferating trichilemmal tumor, a benign tumor of elderly occurs mostly on hair bearing regions such as scalp with history of long duration. Rare sites described include wrist, elbow, mons pubis, vulva, buttock and chest. [1]

The most characteristic feature described for PTT is trichilemmal keratinization and etiologies proposed include trauma and inflammation in TC, a finding further corroborated in our report.

A PTT showing cytologic atypia, abnormal mitosis and infiltrating margins, on the histology, heralds onset of malignancy. Ye et al. described three groups of trichilemmal tumors including Benign, Locally aggressive and Malignant tumors, based on tumor edge characteristic and cytologic anaplasia. [2] The above described groups in the evolution of MPTT were also observed in our case.

Trichilemmal carcinoma, another histological differential, occurs in sun exposed areas and has a tumor with clear cells showing trichilemmal keratinization and shows pagetoid spread in the epidermis or follicular epithelium.

Malignant proliferating trichilemmal tumor behave more aggressively than histologically similar cutaneous SCC, particularly tumors >5 cm or with spindle cell components. [2],[3] Lack of an overlying precursor epidermal lesion such as actinic keratosis favors a diagnosis of MPTT over SCC, a finding that clinched the diagnosis in this case.

Treatment of MPTT is mainly surgical, with wide local excision along with 1 cm margin of normal tissue being the treatment of choice, except for some aggressive variants that are treated with adjuvant radiotherapy. [1],[2],[3] However, cutaneous SCC is treated with surgical excision including Mohs micrographic surgery with radiotherapy being given in cases of incomplete resection. [4],[5]

This case is presented to highlight under diagnosis of MPTT for an SCC, which has different management and prognosis. For this reason the incidence, biological behavior and optimal therapy for MPTT is not well-established. Awareness of differentials in any scalp epithelial neoplasms is the need of the hour, for any reporting pathologist.

   Acknowledgments Top

We acknowledge Dr. Ranjeet S. Gandhi M.S, Gurdwara Bala Sahib Complex, Ring Road, New Delhi - 14 for performing the surgeries.

   References Top

Sau P, Graham JH, Helwig EB. Proliferating epithelial cysts. Clinicopathological analysis of 96 cases. J Cutan Pathol 1995;22:394-406.  Back to cited text no. 1
Ye J, Nappi O, Swanson PE, Patterson JW, Wick MR. Proliferating pilar tumors: A clinicopathologic study of 76 cases with a proposal for definition of benign and malignant variants. Am J Clin Pathol 2004;122:566-74.  Back to cited text no. 2
Satyaprakash AK, Sheehan JS, Sangüez OP. Proliferating trichilemmal tumors: A review of the literature. Dermatol Surg 2007;33:1102-8.  Back to cited text no. 3
Motley R, Kersey P, Lawrence C. Multiprofessional guidelines for the management of the patient with primary cutaneous squamous cell carcinoma. Br J Dermatol 2002;146:18-25.  Back to cited text no. 4
Solan MJ, Brady LW, Binnick SA, Fitzpatrick PJ. Skin. In: Perez CA, Brady LW, editors. Principles and Practice of Radiation Oncology. Philadelphia: Lippincott-Raven; 1997. p. 723-44.  Back to cited text no. 5

Correspondence Address:
Dr. Gargi Tikku
216-C, Shipra Suncity, Indirapuram, Ghaziabad - 201 011, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.142705

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