Surgical excision of pilomatrixoma of the head and neck: A retrospective review of 26 cases.

From the Department of Otolaryngology-Head and Neck Surgery (Dr. Thomas, Dr. Perkins, Dr. Ruegemer) and the Department of Pathology (Dr. Munaretto), Madigan Army Medical Center, Tacoma, Wash.

Reprint requests: R. W. Thomas, DDS, MD, 709 Olympia St., Steilacoom, WA 98388. Phone: [phone]; fax: [phone]; e- mail:[e-mail]

Abstract

The objective of this article is to describe our experiences in treating patients for head and neck pilomatrixoma at our institution during a 5-year period and to compare our findings with previously published results. To that end, we conducted a 5-year retrospective chart review to identify those patients who had a confirmed histopathologic diagnosis of pilomatrixoma involving the head and neck area. We reviewed medical records for presenting signs and symptoms, lesion characteristics, treatment rendered, and outcomes.

We identified 26 patients, aged 6 to 77 (mean: 33), who met the criteria for inclusion in our study. All had been treated for solitary tumors with simple surgical excision and closure. We found no reported adverse outcomes and no tumor recurrences at the surgical sites. These findings support the use of simple surgical excision as the treatment of choice for these tumors.

Introduction

Pilomatrixoma is a benign, usually asymptomatic neoplasm that arises from hair follicle matrix cells. It was originally called a calcifying epithelioma by Malherbe and Chenantais in their initial description in 1880.[1] In 1961, Forbis and Helwig proposed the current name to more accurately reflect the origin of the tumor.[2]

Affected individuals are typically young; peak incidence occurs in patients 8 to 13 years of age. Its prevalence is slightly higher in white females than in other groups.[1-3] The lesions usually appear as firm, solitary, slowly growing, painless tumors of the dermis. They can extend into the subcutaneous tissues and often develop into encapsulated, irregular masses measuring between 0.5 and 5 cm in diameter. The overlying skin may exhibit a faint, bluish-red discoloration on examination. [3,4] The diagnosis can be confirmed by histologic examination.

Treatment consists of surgical excision. Recurrences are rare, but when they do occur, the physician should suspect a malignant pilomatrixoma variant.[3,5] Because most case descriptions are reported in the dermatology literature, otolaryngologists might not be familiar enough with the condition to include it in the differential diagnosis. The purpose of this report is to describe our experience with patients who were treated for a pilomatrixoma at our institution during a 5-year period, and to compare our findings with previously published results. We discuss three specific cases, and we review the literature concerning this neoplasm.

Materials and methods

We conducted a 5-year retrospective chart review to identify those patients who had been treated for pilomatrixoma at our institution between Jan. 1, 1992, and Jan. 1, 1997. All patient medical records or operative reports that listed this as a final diagnosis were selected for detailed study. Patients whose lesions did not involve the head and neck region were excluded from further consideration. Medical records were carefully reviewed for presenting signs and symptoms, lesion characteristics, treatment rendered, and outcomes for all patients who had a final histopathologic diagnosis of pilomatrixoma of the head and neck area. We also examined histopathologic slides.

We also conducted a literature review to identify previously reported cases of pilomatrixoma that involved the head and neck region. Subject headings and title words used for this comprehensive review included pilomatrixoma, pilomatricoma, and calcifying epithelioma of Malherbe.

Results

A total of 56 patients who had had a confirmed histologic diagnosis of pilomatrixoma had undergone surgical excision of their skin lesions at our institution within the designated time frame. Of this group, we identified 26 patients, aged 6 to 77 (mean: 33), whose pilomatrixoma had occurred in the head and neck region, and these 26 were selected for inclusion in this study. When noted in the medical record, most patients reported that their lesion had been present for at least 12 months before they sought treatment.

All 26 patients had been treated for solitary tumors with simple surgical excision and closure. There were no reported adverse outcomes, although one patient had a histopathologic report of an incomplete excision. This patient had no evidence of recurrence 5 months after treatment and has since been lost to followup. During their respective postoperative periods, which ranged from 3 to 37 months, no patient had a reported recurrence of tumor at the surgical site.

Three case studies illustrate the presentations of this type of neoplasm:

Case 1. A 16-year-old boy was referred to the otolaryngology clinic for evaluation of a left preauricular mass that had been present for 18 months. The lesion, which had been progressively growing, was approximately 2 cm in diameter. The patient reported no previous trauma to the area. On examination, various features typical of a pilomatrixoma were present. The lesion was a subcutaneous nodule that was firm and irregular on palpation. The nodule was nontender, and it was mobile over the deeper tissues in the preauricular area. A faint, bluish discoloration was noted through the overlying skin. Following simple excision, histologic examination confirmed the preoperative diagnosis.

Case 2. A 19-year-old woman came to the otolaryngology clinic with a 1-year history of a slowly enlarging left facial mass. The swelling was approximately 2 cm in diameter at its widest point. The mass was mobile and lobulated, and had a bluish-red appearance. There were no palpable intraparotid masses, and all cranial nerves were intact. The lesion was surgically excised and sent for histologic evaluation. A pathology report agreed with the preoperative diagnosis of pilomatrixoma.

Case 3. Examination of a 13-year-old boy revealed a superficial, firm, bluish, 1.5-cm mass on the right posterior neck at the level of the hairline. The lesion had been present for at least 6 months, and it was slowly increasing in size. Fine-needle cytology was performed in the clinic, and a histologic diagnosis of pilomatrixoma was made. The mass was surgically excised, and no recurrence was noted more than 2 years postoperatively.

Discussion

The head and neck region is the most common site of pilomatrixoma; between 56 and 72% of all cases appear in this area. [6-10] The next most common site is the upper extremities. Together, these two sites host the vast majority of these tumors.

Making a clinical diagnosis of pilomatrixoma can be difficult. The differential diagnoses include dermoid and inclusion cysts, preauricular sinuses, hemangiomas, and malignant soft-tissue tumors. Although many possibilities exist, the presence of such a nodule on the head, neck, or upper extremity, especially in a younger patient, should raise the clinician's suspicion of pilomatrixoma.

Fine-needle aspiration of these masses can yield cytologic results that are consistent with pilomatrixoma, although erroneous diagnoses of pilomatrixoma carcinoma have been reported. This exceedingly rare malignant variant of pilomatrixoma is histologically characterized by prominent nucleoli, focal areas of necrosis, and multiple mitotic figures. Even when they extend into subcutaneous tissues, pilomatrixomas typically remain well circumscribed. Histologic examination reveals polygonal basaloid cells with acidophilic cytoplasm and associated foci of calcification. Inflammatory cells as well as ghost, or shadow, cells formed by the keratinization of basaloid cells, are sometimes seen (figure). Evidence of vascular invasion and perineural or perichondrial infiltration support a diagnosis of a more aggressive type of pilomatrixoma that has the potential for malignant degeneration. [5,11,12]

Various imaging methods for evaluating pilomatrixoma have been reported. Plain radiographs of suspicious lesions have limited utility, but they can detect foci of calcification. [13] Preoperative radiographic imaging was not obtained for any of our patients. Computed tomography or magnetic resonance imaging might be considered for those patients who have larger or more unusual tumors. Ultrasonography has been described as a relatively fast and noninvasive investigative technique for estimating the depth of larger masses. [14] The clinically superficial location of most of these tumors makes routine radiographic evaluation unnecessary. An accurate histopatho-logic evaluation is the most important tool for confirming the diagnosis.

Of the 56 patients who had been treated for pilomatrixoma at our institution during the 5-year study period, 26(46%) had lesions that involved the face, a rate that is consistent with previously reported studies. Tumors were most often located in the neck (hair border), scalp, and eyebrow. Only three tumors (11.5%) involved the preauricular area and only three involved the forehead. These two areas have been reported to be common sites of pilomatrixoma, even though they do not feature a particularly high density of hair follicles. Considering the embryology of this neoplasm, it has been theorized that its etiology might be related to specific types of hair. [14]

As a group, our series of patients did not manifest the "typical" presentation variables (table). For example, only 10 of our patients (3 8%) were younger than 20, and only 8(31%) were female. This pattern is easily explained by the fact that our institution is a military medical center, and most patients who are treated there are adult military service members and military retirees.

Depending on the site of involvement, the surgical approach can be modified to ensure the total removal of the lesion without injury to vital neural or vascular structures. For example, a modified Blair incision was used to remove the preauricular tumors of three patients in this series. Their preoperative assessments were consistent with small, superficial neoplasms that were easily removed and did not require facial nerve dissection. Complete surgical excision of the tumor is the recommended treatment, although Morales and McGoey reported that they successfully treated eight patients with incision and curettage of large lesions on exposed sites. [15]

Following excision, pilomatrixoma recurrences are relatively rare, with an overall rate of 2.6% in a large series of patients. [2,6] Our treatment population remained free of recurrence during followup periods that ranged from 3 to 37 months. In the event that a lesion does recur, the physician should suspect pilomatrixoma carcinoma. [4,5,12] The biologic activity of this malignant variant is similar to that of basal cell carcinoma, and aggressive surgical excision remains the recommended treatment of choice.

In conclusion, the results of our patient series support simple surgical excision as the treatment of choice for these tumors.

References

(1.) Malherbe A, Chenantais J. Note sur l'epitheliome calcifie des glandes sebacees. Prog Med (Paris) 1880;S:826-8.

(2.) Forbis R Jr., Heiwig EB. Pilomatrixoma (calcifying epithelioma). Arch Dermatol 1961;83:606-8.

(3.) Singh B, Tolete-Velcek F, Alexis R. Pathological case of the month: Pilomatrixoma. Arch Pediatr Adolesc Med 1995;149:551-2.

(4.) Solanki P, Ramzy I, Durr N, Henkes D. Pilomatrixoma: Cytologic features with differential diagnostic considerations. Arch Pathol Lab Med 1987;l 11:294-7.

(5.) Lopansri S. Mihm MC Jr. Pilomatrix carcinoma or calcifying epitheliocarcinoma of Malherbe: A case report and review of literature. Cancer 1980;45:2368-73.

(6.) Moehlenbeck FW. Pilomatrixoma (calcifying epithelioma): A statistical study. Arch Dermatol 1973;108:532-4.

(7.) Hernandez-Perez E, Cestoni-Parducci RF. Pilomatricoma (calcifying epithelioma): A study of 100 cases in El Salvador. Int J Dermatol 1981;20:491-4.

(8.) Makek M, Franklin DJ, Fisch U. Preauricular pilomatrixoma: A diagnostic pitfall. Oral Surg Oral Med Oral Pathol 1989;68:451-4.

(9.) Brandner MD, Bunkis J. Pilomatrixoma presenting as a parotid mass. Plast Reconstr Surg 1986;78:518-21.

(10.) Hawkins DB, Chen WT. Pilomatrixoma of the head and neck in children. Int J Pediatr Otorhinolaryngol 1985;8:215-23.

(11.) Inglefield CJ, Muir IF, Gray ES. Aggressive pilomatricoma in childhood. Ann Plast Surg 1994;33:656-8.

(12.) Sasaki CT, Yue A, Enriques R. Giant calcifying epithelioma. Arch Otolaryngol 1976;102:753-5.

(13.) Haller JO, Kassner G, Ostrowitz A, et al. Pilomatrixoma (calcifying epithelioma of Malberbe): Radiographic features. Radiology 1977;123:151-3.

(14.) Noguchi H, Hayashibara T, Ono T. A statistical study of calcifying epithelioma, focusing on the sites of origin. J Dermatol 1995;22:24-7.

(15.) Morales A, McGoey J. Pilomatricoma: Treatment by incision and curettement. J Am Acad Dermatol 1980;2:44-6.

                   Location of neoplasms in 26 patients

Pt. Age Sex Site of lesion
 1   6   F  Eyebrow
 2   7   M  Upper eyelid
 3   8   M  Eyebrow
 4  10   M  Neck (posterior)
 5  11   F  Eyebrow
 6  13   M  Neck (posterior)
 7  16   M  Neck (posterior)
 8  16   F  Forehead
 9  16   M  Preauricular
10  19   M  Preauricular
11  21   M  Neck (posterior)
12  23   M  Cheek
13  27   M  Neck (lateral)
14  31   F  Scalp
15  31   M  Eyebrow
16  31   M  Scalp
17  37   M  Scalp
18  45   F  Eyebrow
19  52   F  Scalp
20  54   M  Neck (lateral)
21  56   M  Neck (posterior)
22  57   M  Forehead
23  57   M  Forehead
24  64   F  Preauricular
25  65   F  Scalp
26  77   M  Scalp