BACKGROUND: Pilomatrixoma (pilomatrixoma, calcifying epithelioma of Malherbe) is a relatively uncommon, benign neoplasm arising from the skin adnexa. The tumor can cause diagnostic difficulty not only for the clinician but also for the cytologist.
CASE: A 62-year-old woman presented with a right submandibular swelling of 4 months' duration. The clinical findings were highly suspicious for malignancy. A fine needle aspiration biopsy was performed. Three preliminary differential diagnoses were offered: mucoepidermoid carcinoma of the submandibular salivary gland, squamous cell carcinomatous deposit in a submandibular lymph node and calcifying odontogenic tumor. Computed tomography demonstrated no bony lesion. No primary site of squamous cell carcinoma could be identified. An excisional biopsy of the swelling was performed, and the histologic diagnosis of pilomatrixoma was made.
CONCLUSION: The cytologic presentation of pilomatrixoma of the right submandibular region can masquerade as that of a malignant tumor, in this case mucoepidermoid carcinoma, squamous cell carcinoma or odontogenic tumor. This case delineates the cytomorphologic features of pilomatrixoma that may mimic carcinoma.
Pilomatrixoma is a relatively common benign tumour arising from the matrix and inner sheath of a normal hair follicle as well as hair cortex. It is usually presented as a superficial, solitary, firm mass which is asymptomatic and slowly growing. It accounts for about 0.2% of all routine skin specimens and may poses a diagnostic challenge as it may resemble other common benign lesions found in the head and neck region. We report a case of a 33-year old men presented to us with a pilomatrixoma of the right cheek, surgical management and histological findings.
Pilomatrixoma is a benign tumour that originates from the matrix of the hair root. This rare tumour is usually managed by the dermatologists. The commonest location of this tumour is in the head and neck region; hence, it can be encountered by any doctors with interest in this area. When presented in the neck, this hard tumour may pose a diagnostic challenge. A case report of pilomatrixoma misdiagnosed as a metastatic neck disease from fine-needle aspiration cytology is presented. The mistake in the diagnosis has led to a more aggressive and high morbidity surgery than necessary. It is important that head and neck doctors be aware of this condition and includes it in the differential diagnosis of hard masses presenting in the neck.
Pilomatricoma is an uncommon benign skin tumor arising from the hair follicle. It usually occurs in the head and neck region and is typically found in the pediatric age group particularly girls. The tumor has inconsistent clinical features and may manifest as a small superficial lesion with benign features or a large and seemingly aggressive lesion with local invasion. Due to its variable clinical presentations, it can occasionally be misdiagnosed as a malignant tumor. We encountered a case of pilomatricoma in a 12-year-old girl with a left preauricular swelling for two years, which became progressively larger and more painful in the few weeks before presentation. Clinically, the swelling resembled a malignant parotid tumor. Multiple fine-needle aspirations were performed, but the cytology results were all inconclusive. Subsequent computed tomography scan revealed a well-defined calcified subcutaneous mass with suspicious parotid involvement. The case was posted for tumor excision and superficial parotidectomy. Intraoperatively, however, the mass could be easily separated from the parotid gland. Histopathological examination of the excised specimen showed characteristic ghost cells, basophilic cells, and ossifications typical of pilomatricoma. In conclusion, preauricular pilomatricoma may pose a diagnostic dilemma. A heightened knowledge of the disease is needed for early recognition of its clinical and imaging features to prevent aggressive therapy than is required.
Pilomatricomas can be confidently diagnosed cytologically due to their characteristic cytomorphological features. However, these lesions are rarely encountered by cytopathologists and thus pose a diagnostic dilemma to even experienced individuals, especially when the lesions are focally sampled. We describe two cases of histologically confirmed pilomatricoma. The first case is of a 13-year-old boy with posterior cervical 'lymphadenopathy', and the second one is of a 12-year-old girl with a lower cheek swelling. Both aspirates comprised predominantly atypical basal-like cells, with prominent nucleoli. 'Ghost cells' were readily identified by cell block in case two, but cell block in case one yielded no diagnostic material. In case two, pilomatricoma was accurately diagnosed pre-operatively. A cytological suspicion of a neoplastic process was raised in case one. Despite being diagnostically challenging, pilomatricoma can be diagnosed with careful observation of two unique cytological features of the lesions: (1) pathognomonic 'ghost cells' and (2) irregular, saw-toothed, loosely cohesive basaloid cells, with prominent nucleoli. The role of thorough sampling of the lesion, with multiple passes of various sites, cannot be overemphasized.
A review of consecutive biopsies of adnexal tumours from 112 patients, received by the Department of Pathology, University of Malaya, over a 13-year period was undertaken. The age range of the patients was from 1 to 84 years, with a mean of 29.8 years. Thirty-three (32%) patients were under 20 years of age. There were 68 females with a male to female ratio of 1.0:1.5. In 105 cases (93.7%), the neoplasm was solitary. The tumour measured less than 2 cm in the largest dimension in 103 cases (92%). The common sites of occurrence were the head and neck region (59%) and extremities (25%). Neoplasms of hair follicle origin accounted for 63.4% (71 cases) of all lesions. Intra-tumour deposition of amyloid was noted in one of the 14 cases of trichoepithelioma.