Clinical and Histopathologic Study of 25 Cases with Pilomatricoma / 대한피부과학회지

ABSTRACT

BACKGROUND: Pilomatricoma(Benign calcifying epithelioma of Malherbe) is a uncommon benign tumor with differentiation toward hair cortex cells. It commonly manifests itself as a firm, deep seated nodule with normal Overlying skin, However, anetodermic cutaneous changes have also been described in the literature since 1943. Although the authors hypothesized this phenomenon as a chronic mechanical irritation or a step of transepidermal elimination of the tumoral mass, distinctive elucidation of pathomechanism of it remained. OBJECTIVE: The purpose of this study was to characterize the clinical and histopathologic features of 25 cases with pilomatricoma and to elucidate pathomechanism of the anetodermic cutaneous changes through the comparison of the anetodermic pattern of overlying skin with the changes of the tumoral mass or collagen and elastic fibers in the dermis. METHODS: Twenty-five cases with pilomatricoa have been collected at Chunganam National University Hospital and Kongju Medical Center during 15 years and 5 years, respectively, And we studied the clinical and histopathological characteristics of patients and tried to reveal the relationship between the cutaneous manifestations and the histologic changes through the test for independence. RESULTS: 1. In the age distribution, the patients lesser than 30 years old was 23 cases(92%). The mean age was 18.9 years old. The ratio of males to females was 1 2.6. 2. The duration of lesions was from 2 months to 7 years, with the mean duration of 11 months. The predilection sites were arm(40%), face(28%), neck(12%), shoulder(8%), scalp(4%) and back(4%) in order. All lesions were hard in consistency, and were from bean to walnut sized. Clinically, 10 cases (40%) showed reddish discoloration and/or anetodermic cutaneous changes. 3. Histopathologically, the typical patterns of pilomatricoma were commonly located at the dermis (23 cases) and consisted of the shadow cells predominantly(21 cases). Calcium deposits(21 cases, 84%) were noted within the shadow cells. Eight cases(32%) had the tumoral maese demarcated with fibrous capsules, and the foreign body reaction with giant cells and chronic mononuclear cell infiltrations around the shadow cells ruptured the fibrous capsules in 17 cases(68%). 4. When we compared the relationship between the inflammatory cell infiltrations around the tumoral mass and the changes of dermal collagen and elastic fibers, we observed that the changes of dermal fibers and foreign body reaction and mononuolear cell infiltrations were statistically co-related. When compared the cutaneous changes with the inflammatory cell infiltrations of the tumoral masses, we could also reveal that the anetodermic cutaneous changes of the overlying skin might be influenced by the foreign body reactions with chronic mononulcer cell. Based on the status of foreing body reaction, the average of onset was inversely proportional to the average of age. CONCLUSION: Pilomatricomas are slowly growing, firm, deep seated benign tumor which occurs commonly on the arm, face and neck. However, they often showed the anetodermic changes on the overlying skin. Anetodermic cutaneous changes or discoloration may be correlated with the degree of foreign body reactions without the evidences of transepidermal elimination histopathologically.