Turkish Journal of Plastic Surgery

: 2020  |  Volume : 28  |  Issue : 4  |  Page : 248--251

Giant pilomatrixoma revisited

Aydan Ayse Kose, A Emre Kocman 
 Department of Plastic, Reconstructive and Aesthetic Surgery, Eskişehir Osmangazi University, Eskişehir, Turkey

Correspondence Address:
Dr. Aydan Ayse Kose
Department of Plastic, Reconstructive and Aesthetic Surgery, Medical School, Eski.ehir Osmangazi University, Me.elik 26480, Eski.ehir


Pilomatrixoma is a common benign tumor of childhood; however, the correct diagnosis is rare. The fast-growing, giant pilomatrixomas frequently confused with some other malign conditions necessitating excess workup and over surgeries. The aim of this review is to identify the specific presenting complaints of the patients, clinical and radiological findings. A 13-year-old adolescent male patient was presented with a rapidly growing, large, solid cheek mass. The mass was removed from an intraoral mucosal incision. Although the patient had an infection after the surgery, the postoperative course was otherwise unremarkable, and the patient had no incision scar on the cheek. The initial diagnosis for rapidly growing masses is generally infection and malignity. When the presurgical diagnostic tests are not interpretational, total extirpation and pathological examinations are necessary. Pilomatrixoma, as a very common benign childhood tumor, has specific clinical features that may remind the entity to the physician. During the diagnosis of fast-growing, painless, large masses of head, neck, and upper extremities, pilomatrixoma should be among the differential diagnosis. By looking for the tent and seesaw signs, one can avoid the unnecessary workup for pilomatrixoma.

How to cite this article:
Kose AA, Kocman A E. Giant pilomatrixoma revisited.Turk J Plast Surg 2020;28:248-251

How to cite this URL:
Kose AA, Kocman A E. Giant pilomatrixoma revisited. Turk J Plast Surg [serial online] 2020 [cited 2022 Dec 8 ];28:248-251
Available from: http://www.turkjplastsurg.org/text.asp?2020/28/4/248/296469

Full Text


Pilomatrixoma or pilomatricoma is a benign tumor originating from the hair matrix, cortex, and the epithelial sheath.[1] Pilomatrixoma is the second most common benign tumor emerging in childhood after the epidermal cyst. Although pilomatrixoma is very prevalent, it is often diagnosed with epidermoid cyst. Pilomatrixoma is also known as calcifying epithelioma of Malherbe, after the proposed origin of the sebaceous glands by Malherbe, which was later renamed by Forbis and Helwig[2] into pilomatrixoma to emphasize the matrix of the hair root origin etymologically correctly.

Pilomatrixoma is known to be a slow-growing tumor that is usually present with a bimodal distribution in children and adults over 60 years.[3] It also exhibits a higher prevalence in females.

Lesions are generally located at the head and neck, with sizes varying from 0.5 to 3 cm in diameter. Lesions of size >5 cm have also been reported in literature and are named giant pilomatrixomas.

We report a case of fast-growing giant pilomatrixoma. Our aim is to highlight pilomatrixoma as a probable diagnosis of noncongenital fast-growing masses at the head-and-neck area in children.

 Case Report

A 13-year-old male patient was brought to our hospital, presenting a mass located in the left cheek, which initially appeared as a small mass 6 months ago and kept growing [Figure 1]. The patient denied any pain and reported no trauma history in the relevant area. Physical examination revealed a subdermal, solid, painless mass of approximately 7 cm diameter that could not be differentiated from the surrounding tissue with palpation. The most projectile area of the mass seemed adherent to the skin above it where it also caused purple discoloration [Figure 2]. Intraoral examination showed that it was free from the mucosa above it. Facial nerve examination was unremarkable.{Figure 1}{Figure 2}

In an ultrasonographic examination made by an outside facility, 3 months prior to the patient's admission, a bold, irregular contour image of a necrotic lesion of 12 mm × 9 mm was reported. Magnetic resonance imaging (MRI) scan was requested based on a history of fast growth and a suspicion of the mass being malignant to understand the structure of a lesion. The results indicated a mass lesion of 42 mm × 22 mm, densely colored in the perimeter, and slightly in the central [Figure 3]. Radiologically, these results likely suggested a schwannoma or less likely a benign mesenchymal mass. In addition, although the mass was observed to be in close proximity to the skin, a tissue plane was detected between the skin and the mass border.{Figure 3}

The patient was taken into surgery under general anesthesia, and the encapsulated mass was removed through mucosal incision and was sent to pathological examination [Figure 4]. Examination of the specimen was reported to be a pilomatrixoma. The patient was discharged on postoperative day 2, only to be readmitted back due to infection caused by the lack of hygiene and was treated with antibiotherapy. The following period was unremarkable, and the patient did not have any functional or esthetic problems [Figure 5].{Figure 4}{Figure 5}

Written consent was obtained from the father.


Pilomatrixoma is the most common benign tumor of childhood. Its general frequency of 0.03%–0.1% makes it difficult for pilomatrixoma to be the initially suspected entity by clinicians among the masses of similar localization and physical attributes. It is commonly localized in the head-and-neck region and upper extremities. Physical examination reveals a near-bone hard, mobile/semi-mobile mass which is located in the sub-dermis and usually found as a slow-growing, painless, and solid nodule. The skin over the mass is usually unremarkable; however, superficial lesions can give the skin a bluish-reddish shade.[4],[5] In terms of the diagnosis, it can be confused with many benign and malignant entities, starting with epidermoid cysts. Tent and seesaw signs are those that would make pilomatrixoma a possible diagnosis. The formation of many sides and angles caused by stretching the skin on a pilomatrixoma has been described as a tent sign by Graham and Merwin[6] and has been accepted as a pathognomonic sign of this lesion.[7] This sign is caused by the spherical-smooth surface of the lesion turning irregular due to the accumulation of calcium inside the lesion.[8] The seesaw sign has been defined as the rise of one side of the lesion as a result of pressing on the other side.[9]

Although the signs distinctive for pilomatrixoma has been described, the rate of correct preoperative diagnosis with physical examination has been reported as 28.9%–58%.[10],[11] This low rate of diagnosis can be explained by the lack of progenitor lesions and a specific history in the case of pilomatrixomas. In Hernández-Núñez et al.'s[1] series of 239 patients, only 9% of the patients reported a prior history of recognizable trauma, although the authors have noted that the association could have been coincidental considering the high frequency of pilomatrixomas in the childhood age.

In our clinical experience, pilomatrixomas generally give the impression of a subdermal, irregularly-sided cystic mass with yellow–white content [Figure 6]. Although these signs were not present in this patient, the blue–purple discoloration described by Pant et al.[4] and Aydin et al.[5] was present. We believe this sign to be a result of the inflammation and the accumulation of inflammatory cells between the skin and the fast-growing mass, hinting that the mass can be perforated.[12]{Figure 6}

In our case, no signs such as tent/seesaw were present to directly indicate pilomatrixoma. No white shading that would indicate the lesion's calcific content was observed. The patient lacked any accompanying pathologies that are thought to be associated with pilomatrixoma such as myotonic dystrophy, Rubinstein–Taybi syndrome, Turner syndrome, Gardner syndrome, xeroderma pigmentosum, and basal cell carcinoma.[10] Also we could not find any mention of undescended testes co-occurrence with pilomatrixoma in the literature, stated in our patient's history.

There is a significant amount of papers dealing with the ultrasonography, tomography, and MRI of pilomatrixomas. In ultrasonography, heterogeneously hyperechoic or homogeneously hyperechoic points are usually observed as an indicator of calcification.[11] In our patient's ultrasonography results, the image was reported to be of necrotic structure without any details, inconsistent with the findings described in the literature. Nevertheless, necrotic content can be found in many benign and malignant lesions as a result of fast growth.

Studies about pilomatrixomas diagnostic methods have increased in the past decade. The characteristics of computerized tomography (CT) and MRI images have been described in detail by relevant papers. A typical CT finding is a distinctively bordered soft-tissue mass of varying calcification. In MRIs, pilomatrixomas display a homogeneous intermediate signal intensity on T1-weighted (T1W) images and inhomogeneous signal intensity on T2W images. Hyperintense reticulations are also the characteristic findings of gadolinium-enhanced T1W and T2W images. Hyperintense reticulations resemble multiple, small, ring-shaped hypointense structures named accompanied with peripheral hyperintense areas, named “fascicular” sign, and is a sign of schwannoma in fat-suppressed T2W images. For this reason, schwannoma can be included in the differential diagnosis of MRI inspections. However, schwannoma's deeper localization and the possession of a hypointense rim corresponding to the fibrous capsule on T2W images are signs distinctive from pilomatrixomas. Although epidermal cysts are prominent entities in clinical diagnosis, they can be easily differentiated from pilomatrixomas with their cystic appearances on MRI.[13]

Pilomatrixomas do not shrink or disappear on their own; however, perforated ones can get smaller due to drainage. This lesion that is usually found in the lower dermis can extend to the subcutis, and if it is located in the superficial dermis, especially papillary dermis, it might perforate to the epidermis. This process is called transdermal elimination.[14]

Cytological diagnosis has been used in cases where the diagnosis was difficult. The use of fine-needle aspiration biopsy (FNAB) can also be used as a diagnostic method in special localizations that could be confused with malignant tumors. In classic cytological profile, basaloid and ghost cells are expected to be detected; however, if the basaloid cells are increased in the aspirate, the likelihood of mistaking it for malignancy increases. Aydin et al. reported that after CT and MRIs nonspecific findings not contributing to diagnosis, FNAB also resulted in false results.[4] Consequently, it could be said that FNAB is not a definitive step in pilomatrixoma diagnosis.

Histopathologically, pilomatrixomas are composed of irregularly shaped islands of epithelial cells arranged in a circular pattern, surrounded by a fibrous capsule. The epithelial cells that make up the islands are made from basaloid cells in the peripheral and keratinized basaloid cells called ghost cells in the center. Calcification is observed in many of the cases.[14]

For the treatment of pilomatrixoma, the mass should be excised completely from the boundary of the healthy tissue; otherwise relapses have been reported to potentially occur. Due to their frequent localization in the head-and-neck area, their reconstructions are cosmetically and functionally important. Following preoperative examinations of our patient which did not indicate malignancy, excision of the mass through intraoral buccal approach was preferred. The enclosure of the mass by a thin capsule eases the extirpation, however, in regions where the surface dermis is closer to the epidermis due to thinning, precise dissection of the mass and the healthy tissue is essential for the nonperforation of the surface skin. In the related literature, the cases in which giant pilomatrixomas were close to the skin or perforated to the skin, often treated with wide resections and advanced reconstructive methods.[4],[15],[16] Despite the various diagnostic efforts, these reports all share a common point of being undiagnosed, fastgrowing, and relapsing pilomatrixomas. Furthermore they all highlight the importance of early diagnosis and excision with sufficient surgical margin.


TFor the fast.growing solid masses of the head and neck and upper extremities, giant pilomatrixoma should be one of the initial diagnosis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient's parents have given their consent for the patient's images and other clinical information to be reported in the journal. The patient's parents understand that the patient's name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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