Answer of Dermatopathology Case 23

Pilomatrixoma (Pilomatricoma ; Calcifying epithelioma of Malherbe)


Visit: Pathology of Pilomatrixoma
Visit: Dermatopathology site


Abstract:

Fine needle aspiration cytology of pilomatrixoma and differential diagnoses.Acta Cytol. 2009 Nov-Dec;53(6):683-8.
OBJECTIVE: To review the cytologic features of pilomatrixoma to allow a definitive diagnosis at the time of aspiration and correct patient management. STUDY DESIGN: Three patients each presented with a mass lesion and on fine needle aspiration were diagnosed as either having pilomatrixoma or a benign skin adnexal tumor. The diagnosis was confirmed on histology. A retrospective analysis of the cytology was performed. RESULT: The most consistent and predominant features for diagnosis were basaloid cells, anucleate squamous cells and calcification in an inflammatory background, often with giant cells. Only focal evidence of true shadow or "ghost" cells was seen in one case on the Diff-Quik smear. Therefore, lack of shadow cells does not preclude correct diagnosis in the presence of theother relevant cytologic features. If all the major components of pilomatrixoma are present in an aspirate, the diagnosis should not be problematic. However, if one component predominates, this may lead to an erroneous diagnosis of otherbenign and malignant lesions. CONCLUSION: Knowledge of the cytologic features of pilomatrixoma will allow correct patient diagnosis and management.

Pilomatrixoma of the forearm: a case report.Iowa Orthop J. 2009;29:121-3. Pilomatrixoma is a benign neoplasm derived from hair follicle matrix cells. Involvement of the upper extremities is relatively uncommon and can be mistaken for malignancy. We present the case of a 52-year-old woman with a pilomatrixoma of the forearm, and we review the literature regarding pilomatrixomas in the upper extremity.

Recurrent pilomatricoma on the left eyebrow: case report. Arq Bras Oftalmol. 2009 May-Jun;72(3):380-3.
Pilomatricoma is a benign neoplasm originated in the pilosebaceous follicle which appears as an intradermal nodule during childhood, in most cases. It is generally covered with normal skin, reaching a diameter of 1.5 cm on average, and it often shows no recurrence after surgical excision. The authors describe a case in whicha 26-year-old patient presented a tumoral lesion on the upper left superciliary area was submitted to total excision, and diagnosed as pilomatricoma by the histological study. According to the patient, this lesion had a progressive and slow growth of about two years. Eight months after the first surgical intervention, there was a new tumor growth in the region, this time quicker and worsen, with ulceration on the small skin area that covered the lesion, thus leading to malignity suspicion. After the conduction of a new excision within a security margin, the histological test confirmed that it was a pilomatricoma lesion and the piece displayed no sign of malignity. The patient has been followed up for one year, showing no signs of recurrence so far.

Pilomatricoma can differentiate not only towards hair matrix and hair cortex, but also follicular infundibulum, outer root sheath and hair bulge. Exp Dermatol. 2009 Aug;18(8):734-7. Epub 2009 Mar 16.
Pilomatricoma is believed to differentiate towards the hair matrix and hair cortex. To elucidate the origin of differentiation in pilomatricoma, we studied the expression of epithelial keratin (K) and filaggrin (filament aggregating protein) in pilomatricoma. An immunohistochemical study has been made of 53 casesof pilomatricoma using 10 monospecific anti-keratin antibodies and anti-filaggrin antibody. Basophilic cells, transitional cells and shadow cells did not reactwith epithelial keratins and filaggrin antibodies as well as hair matrix and haircortex. Instead, infundibular-type epithelium was positive for K1, K10 andfilaggrin. Epithelium showing trichilemmal keratinization was positive for K14 and K16. The hair bulge-like structure was positive for K19. The differentiation of pilomatricoma is diversified, and is heterogeneous in epithelial keratin and filaggrin expression. Our results for keratin and filaggrin expression suggested that pilomatricoma can differentiate not only towards hair matrix and haircortex, but also follicular infundibulum, outer root sheath and hair bulge.

Pilomatrixoma of the ocular adnexae: clinical and histologic analysis (13 cases). Klin Monbl Augenheilkd. 2009 May;226(5) :404-8. Epub 2009 Apr 27.
BACKGROUND: Pilomatrixoma (calcifying epithelioma of Malherbe) is a rare benign tumour originating from the matrix of the hair root. In this study, we evaluated the clinical and histopathological characteristics of all the respective tumour specimens submitted to our laboratory since 1997. PATIENTS/MATERIALS AND METHODS:We reviewed the clinical and histologic findings of 13 pilomatrixomas localised to the ocular adnexae. Paraffin sections were stained with H&E and PAS and, inaddition, immunohistochemistry was performed using markers for macrophages (CD68), for proliferative activity (Ki67), and for proliferation/apoptosis(CAS/CSE1L). RESULTS: All 13 pilomatrixomas were of reddish-livid colour andlocalised on the upper eyelid and/or near the eyebrow. The patients ages ranged from 4 to 84 years without preference for either gender. In 3 cases the correct diagnosis was made intraoperatively, while no pilomatrixoma was diagnosed priorto surgery. The most frequent false diagnoses were retention cyst (n = 3),atheroma (n = 2), and abscess (n = 2). There was no tumour recurrence in any of the cases within the time period presented. All 13 pilomatrixomas demonstrated the characteristic histology with areas of basophilic islands, shadow cells, calcification and a chronic granulomatous inflammation with foreign body giant cells in varying amounts. Immunhistochemical staining with anti-Ki67 andanti-CAS/CSE1L indicated a regular cellular maturation of the basophilic cells. No correlation was found between any of the histological or immunohistochemical markers and clinical parameters such as size, age and gender of the patient and duration of tumour presence prior to surgery. CONCLUSIONS: This case series represents one of the largest published so far, and underscores that pilomatrixoma can appear at any age. While it is usually not recognised clinically, it should be considered in the differential diagnosis especially for tumours of the upper eyelid. Our immunohistochemical findings support the basically benign nature of a pilomatrixoma but also point to the chronic inflammatory stimulus that can lead to complications after incomplete removal.