Pilomatricoma in the head and neck: CT findings in three patients

Huge pilomatrixomas of the scalp: A case report

Pilomatrixoma is a rare benign skin tumor differentiating toward hair matrix cells usually encountered in the head and neck region. It is most frequently appearing in the first and second decades of life. Histopathological examination is essential to make definitive diagnosis. Herein, we present an atypical case of multiple pilomatrixomas. A 69-year-old man with multiple voluminous masses over the scalp. Among the three lesions, one was clinically suspicious for malignancy, it measured 17 cm and was ulcerated in places. Histopathology confirmed the diagnosis of pilomatrixoma. The tumors were removed surgically with free margins. Otolaryngologist should be familiar with this benign tumor when evaluating soft-tissue mass in the head and neck region.

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Pilomatrixoma, is a particular and uncommon type benign subcutaneous tumors arising from the cutaneous adnexa.

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Otolaryngologist should be familiar with this benign tumor when evaluating soft-tissue mass in the head and neck region.

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Clinical follow-up of these lesions is necessary to avoid recurrence and malignant transformation.

A new case of the pilomatrixoma rare in the preauricular region and review of series of cases

Pilomatrixoma is considered a rare benign tumor arising from the hair follicle, most common in the head and neck region, but it is rarely diagnosed on a clinical basis. This report describes a new case of giant pilomatrixoma in a 36-year-old female patient. The nodule was localized in the preauricular area on the right side, appearing as a slow-growing, fixed, painless, with a hardened consistency, unusual giant (4.5 cm). A cone-beam computed tomography (CBCT) examination showed a slightly hyperdense lesion, and fine-needle aspiration cytology (FNAC) revealed peripheral blood and mononucleated inflammatory cells. After enucleation of lesion, a diagnosis of pilomatrixoma was confirmed. The differential diagnosis of pilomatrixoma is broad, because its characteristics also can be found in other lesions common to the head and neck. Thus, a lesion in the head and neck, adherent to the skin, and well demarcated, mainly in the young and in females, should be suspected as pilomatrixoma.

MR imaging findings of pilomatricomas: a radiological-pathological correlation

BACKGROUND

Magnetic resonance imaging (MRI) findings of pilomatricomas have yet to be determined.

PURPOSE

To assess the correlation between MRI and pathological findings of pilomatricomas.

MATERIAL AND METHODS

MR images were obtained on patients with histologically proven pilomatricomas using a 1.5-T MR scanner. The images were retrospectively reviewed for size, signal intensity compared with skeletal muscles, and enhancement patterns. Furthermore, we assessed the presence of a reticular appearance, a ring-like appearance, and peritumoral fat stranding.

RESULTS

We included 11 consecutive patients with 12 histologically proven pilomatricomas (3 boys/men, 8 girls/women; age range, 4-76 years; mean age, 20 years; median age, 14 years). The tumors were located in the head and neck (n = 6), upper extremities (n = 5), and lower extremities (n = 1). The maximum tumor diameter was in the range of 7-32 mm (mean, 16.5 mm). On T2-weighted (T2W) images, five tumors showed homogeneous hypointensity, whereas six showed reticular hyperintensity and one showed cystic hyperintensity. On fat-suppressed T2W images, nine tumors showed reticular hyperintensity, eight showed ring-like hyperintensity, and five showed peritumoral fat stranding. On fat-suppressed gadolinium-enhanced T1-weighted (T1W) images, one tumor showed no enhancement, whereas three showed reticular enhancement and five showed ring-like enhancement. Histologically, edematous and fibrous stroma was observed in 10 tumors, tumor capsules in 11, and inflammatory cell infiltration of the peritumoral fat tissue in nine.

CONCLUSION

MRI features of pilomatricomas included reticular and ring-like hyperintensities on fat-suppressed T2W images and reticular and ring-like enhancement on fat-suppressed gadolinium-enhanced T1W images.

Pilomatricomas: the diagnostic value of ultrasound

OBJECTIVE

The purpose of this study was to analyze statistically significant diagnostic factors for pilomatricoma on the basis of ultrasonographic features.

METHODS

Sonographic images were retrospectively reviewed from 44 pilomatricomas, and from 43 control subjects with other subcutaneous tumors. Two radiologists determined the tumoral shape, margin, echotexture, echogenicity, posterior shadowing, posterior enhancement, hypoechoic rim, internal calcification, and vascularity.

RESULTS

The reliable diagnostic factors for pilomatricoma were hypoechogenicity (P < 0.001), heterogenicity (P < 0.05), internal calcification (P < 0.001), hypoechoic rim (P < 0.001), and posterior shadowing (P < 0.001). Scattered dots were the most common patterns of internal calcification. A combination of hypoechogenicity, heterogenicity, internal calcification of scattered-dot pattern, and a hypoechoic rim was a statistically significant difference between the two groups (P < 0.001; odds ratio, 21).

CONCLUSIONS

The features of heterogeneous echotexture, internal echogenic foci in scattered-dot pattern, and a hypoechoic rim or posterior shadowing itself could be discriminative ultrasonographic criteria for differentiating pilomatricomas from other subcutaneous tumors.

Pilomatricomas in children: imaging characteristics with pathologic correlation

BACKGROUND

Although pilomatricoma commonly occurs in children, there is still a poor understanding of the imaging characteristics of pilomatricoma and lack of agreement regarding its imaging findings and histopathologic features.

OBJECTIVES

To characterize the radiologic appearance of pilomatricomas on US, CT, and MR and to correlate the imaging findings with histopathologic features.

MATERIALS AND METHODS

The imaging findings of 47 pilomatricomas on US (n = 17), CT (n = 31), and MR (n = 5) were retrospectively evaluated. Pathologic specimens of all cases were reviewed and compared with imaging findings.

RESULTS

All lesions were well-circumscribed, subcutaneous nodules with partial attachment to the overlying skin. On US, the lesions were mostly hyperechoic with posterior acoustic shadowing and hypoechoic rim. On CT, they appeared as enhancing soft-tissue masses with varying amounts of calcification. MR findings were internal reticulations and patchy areas on T2-weighted images and contrast-enhanced T1-weighted images, corresponding to edematous stroma on pathology. Peritumoral inflammatory changes and connective capsule on pathology were well correlated with imaging findings.

CONCLUSION

Pilomatricoma should be considered when US or CT shows a well-defined hyperechoic or calcific nodule in subcutaneous fat attached to the skin in children. MR images may be helpful in diagnosis. Pathologic findings are well correlated with imaging findings.

The common ultrasonographic features of pilomatricoma

OBJECTIVES

The purpose of this series was to describe typical ultrasonographic features of 20 cases of pilomatricoma and to improve its diagnostic rate with the use of an ultrasonographic approach.

METHODS

For 20 pilomatricomas in 19 patients with preoperative ultrasonography from 1995 to 2004, we reviewed age, sex, symptoms, duration, referring clinician, and tumor sites. The ultrasonographic findings were retrospectively analyzed for tumor location, shape, size, margin, echo texture, echogenicity, presence, amount, and shape of calcification, presence of a hypoechoic rim, and Doppler flow pattern.

RESULTS

The mean age of the 19 patients was 6.9 years (range, 1-21 years), and the female-male ratio was 1.1:1. Patients had a painful palpable mass in 10 cases (50%). Nine lesions occurred in the neck, 5 in the cheek, 2 in the preauricular region, and 4 in the extremity. All tumors were located in the subcutaneous layer. The mean size of the tumors was 13.4 mm. Fourteen pilomatricomas (70%) appeared as well-defined oval masses. Tumors were heterogeneously hyperechoic in 80% of cases. All tumors had internal echogenic foci. A hypoechoic rim was seen in 17 cases (85%). Doppler flow signals were observed in the peripheral region in 14 cases (70%). A correct preoperative diagnosis was made in 33% on the basis of clinical findings and in 76% by ultrasonography.

CONCLUSIONS

Diagnosis of pilomatricoma should be considered when a well-defined mass with inner echogenic foci and a peripheral hypoechoic rim or a completely echogenic mass with strong posterior acoustic shadowing in the subcutaneous layer of the head, neck, or extremity is found on ultrasonography.

[Pilomatrixoma as a problem in ophthalmic surgery]

Pilomatricoma, relatively rare benign tumour of the hair matrix cells, is usually misdiagnosed preoperatively. This result in unnecessary extensive surgery. In order to improve diagnosis and treatment of pilomatricoma, authors discuss their ten years experience (28 cases) with this tumour.