Abstract | November 17, 2023

Giant Pilomatrixoma Removed from the Temporal Scalp

Kelsey Hayes, BS, OMS IV, Arkansas College of Osteopathic Medicine, Fort Smith, AR

Kirby Curtis, BS, OMS IV, New York Institute of Technology College of Osteopathic Medicine, Jonesboro, AR; Alexandros Georgolios, MD, Otorhinolaryngology, Poplar Bluff Regional Medical Center, Poplar Bluff, MO

Learning Objectives

  1. Identify pilomatrixoma as a rare benign tumor that originates from the hair matrix cells in the hair follicle and usually presents as a solitary, firm, slow-growing nodule in the head and neck region.
  2. Diagnose pilomatrixoma by histological examination features, treat with surgical removal utilizing clear margins, and cite guidelines for monitoring patients for recurrence.
  3. Discuss the importance of considering benign tumors such as pilomatrixoma in the differential diagnosis of scalp masses and the need to promptly exclude malignancy as many giant pilomatrixomas are clinically suspicious for malignant tumors.

Introduction: Pilomatrixoma (calcifying epithelioma of Malherbe or pilomatricoma) is a rare benign tumor that originates from the germinal matrix cells in the hair follicle. A giant pilomatrixoma is a rare clinical variant owing to a size greater than 5 cm. The reported incidence of diagnosis is between 0.001% and 0.0031% of dermato-histopathologic materials submitted for examination. The tumor typically presents as a solitary, firm, slow-growing nodule in the head and neck region, but it can also occur in the trunk and extremities. Although pilomatrixoma is usually benign, it can be mistaken for malignant tumors, such as basal cell carcinoma or squamous cell carcinoma. Therefore, histologic examination is crucial to confirm the diagnosis and differentiate it from malignant tumors. The histopathologic exam is significant for presence of basaloid and ghost cells with the occasional multi-nucleated giant cell.

Case presentation: A patient presented to the otolaryngology clinic with a nodule on the left scalp that had been progressively increasing in size for the past 8 months. On examination, a 6-7 cm firm and non-tender well-circumscribed subcutaneous nodule was found over the left temple. There was no ulceration or induration of the skin noted. There was no palpable lymphadenopathy of the cervical nodes. Due to the firm nodule palpated, the stark size of the nodule, and a history of smoking there was great concern for malignancy. A CT scan of the head revealed a round, well-defined soft tissue lesion in the left frontotemporal subcutaneous scalp. There was no significant enhancement of the lesion, suggesting a benign lesion.

Final diagnosis: The patient elected to have the nodule removed surgically under general anesthesia in the operating room. Microscopic examination revealed islands of basaloid and ghost cells with the occasional multi-nucleated giant cell, consistent with the diagnosis of pilomatrixoma. Due to the gross size of the lesion being greater than 5 cm, the diagnosis of giant pilomatrixoma was made.

Management: The patient recovered well postoperatively. The patient was evaluated in the outpatient clinic one week post-operative without sign of recurrence. The patient will be monitored every three months for the next year for recurrence.

References and Resources

  1. DeRosa DC, Lin-Hurtubise K. Pilomatricoma: an unusual dermatologic neoplasm. Hawaii J Med Public Health. 2012 Oct;71(10):282-6. PMID: 23115748; PMCID: PMC3484971.
  2. Wydadi O, Bijou W, Laachoubi M, Oukessou Y, Roubal M, Mahtar M. Huge pilomatrixomas of the scalp: A case report. Int J Surg Case Rep. 2021 Jul;84:106048. doi: 10.1016/j.ijscr.2021.106048. Epub 2021 May 29. PMID: 34174742; PMCID: PMC8234360.
  3. Sabater-Abad J, Matellanes-Palacios M, Bou-Boluda L, Campos-Dana JJ, Alemany-Monraval P, Millán-Parrilla F. Giant pilomatrixoma: a distinctive clinical variant: a new case and review of the literature. Dermatology Online Journal [Internet]. 2020 [cited 2023 Apr 26];(8).
  4. Fulton EH, Kaley JR, Gardner JM. Skin Adnexal Tumors in Plain Language: A Practical Approach for the General Surgical Pathologist. Arch Pathol Lab Med. 2019 Jul;143(7):832-851. doi: 10.5858/arpa.2018-0189-RA. Epub 2019 Jan 14. PMID: 30638401.
  5. Marino MA, Ascenti G, Cardia R, Ieni A, Colonna MR. Pilomatrixoma of the right thigh: Sonographic-pathologic correlation in a young man. Radiol Case Rep. 2019 Dec 25;15(3):230-233. doi: 10.1016/j.radcr.2019.11.007. PMID: 32071653; PMCID: PMC7010961.
  6. Nadershah M, Alshadwi A, Salama A. Recurrent giant pilomatrixoma of the face: a case report and review of the literature. Case Rep Dent. 2012;2012:197273. doi: 10.1155/2012/197273. Epub 2012 Oct 18. PMID: 23119187; PMCID: PMC3483657.
  7. Marzouki A, Chbani B, Bennani A, Lahrach K, Boutayeb F. Giant pilomatricoma of the arm: An unusual presentation (A case report) Journal of the Saudi Society of Dermatology & Dermatologic Surgery, Volume 17, Issue 1,2013, Pages 33-35. ISSN 2210-836X. https://doi.org/10.1016/j.jssdds.2012.12.004.
  8. Subramanyam C, Dyrek P, Yao X, Kay MH. Malignant Pilomatricoma of the Lower Extremity: A Difficult and Rare Diagnosis. Cureus. 2022 Feb 6;14(2):e21957. doi: 10.7759/cureus.21957. PMID: 35282549; PMCID: PMC8903812.
  9. Beattie G, Tai C, Pinar Karakas S, Cham E, Idowu O, Kim S. Colossal pilomatrixoma. Ann R Coll Surg Engl. 2018 Feb;100(2):e38-e40. doi: 10.1308/rcsann.2017.0196. Epub 2017 Nov 28. PMID: 29182000; PMCID: PMC5838698.
  10. Egger A, Li Y, Gonzalez ME. A Case Report of a Rapidly Growing Giant Pilomatrixoma on the Posterior Shoulder in a 12-Year-Old Male Patient. Skin Appendage Disord. 2020 Jul;6(4):240-243. doi: 10.1159/000507641. Epub 2020 Jun 3. PMID: 32903889; PMCID: PMC7445540.
  11. Lazar A, Calonje E, Grayson W, Dei Tos A, Mihm M, Redston M, McKee P. Pilomatrix carcinomas contain mutations in CTNNB1, the gene encoding β-catenin. (2005) Journal of Cutaneous Pathology, 32: 148-157. https://doi.org/10.1111/j.0303-6987.2005.00267.x
  12. Adhikari G, Jadhav GS. Giant Pilomatrixoma of the Scrotum: A Rare Case Presentation. Cureus. 2022 Feb 15;14(2):e22228. doi: 10.7759/cureus.22228. PMID: 35340505; PMCID: PMC8930436.
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