Abstract. Pilomatrix carcinoma (PC) is a rare neoplasm, particularly in the parotid region. Thus, it is easily misdiagnosed and an optimal treatment regimen has not yet been established. The present study reports the case of a 43-year-old female who presented with a PC of the parotid region and reviews the associated published literature. The patient underwent three surgical excisions prior to the tumor being completely removed, and was misdiagnosed four times prior to the correct diagnosis. Once the tumor was completely removed, the patient received radiation therapy (RT). At the 2-year follow-up, the patient remained free of local recurrence and metastasis. To the best of our knowledge, only 3 cases of PC on the parotid region have been reported. Although an optimal treatment regimen has not been established, surgery with wide margins is recommended, with RT and chemotherapy producing mixed results.
IntroductionPilomatrix carcinoma (PC) is a rare and malignant adnexal tumor of hair matrix origin (1). The tumor is a dermo-hypodermic in nature, with a low metastatic potential, but a high risk of recurrence following excision. PC is characterized by a locally-aggressive and low-potential malignant lesion, which is likely to be misdiagnosed. However, distant metastasis and mortality have also been reported (2). To highlight a further case of this extremely rare occurrence, the present study reports a case of PC of the parotid region that was misdiagnosed numerous times, and reviews the pertinent literature.
Case reportA 43-year-old female first visited the Department of Head and Neck Surgery of Jiangyou City People's Hospital (Jiangyou, Sichuan, China) in 2009 due to a tenacious subcutaneous nodule that was 1.0 cm in diameter on the left side of the parotid region. The small, subcutaneous nodule was asymptomatic, and had been slowly increasing in size for the past 5 years. The nodule was surgically excised under local anesthesia with a false clinical diagnosis of an adenolymphoma of the parotid gland. However, 1 year later, a tenacious mass with an unclear boundary reappeared at the previous site. A secondary excision was performed at the same hospital, and the histological evaluation revealed a squamous epithelial cell mass and cells with hyperchromatic nuclei among fibrous tissue, reactive hyperplasia of the lymph node and partial epithelial proliferation among the tissues. A gray-black nodule with swelling and effusion appeared 3 months later at the site of the primary lesion. The patient was admitted to the same hospital once more. A biopsy of the nodes revealed a well-differentiated squamous cancer. The patient was then transferred to our hospital for further diagnosis and therapy.Upon physical examination, a 2.0x2.0-cm, tender, firm, non-fluctuant, gray-black lesion was noted on the skin surface of the left side of the parotid region (Fig. 1). There was no palpable lymphadenopathy of the left side of the neck. Sensation around the area and salivation were normal. There was no facial nerve dysfunction or dete...