UPMC Dermatopathology "Case of the Month" Presentations
UPP - Department of Dermatology, Dermatopathology Unit
Case Authors: Carol Roper MD, Larisa Geskin MD, Drazen Jukic MD PhD
DECEMBER 2004 CASE OF THE MONTH
DISCUSSION & DIAGNOSIS
DIAGNOSIS
Final Diagnosis: A diagnosis of pilomatricoma, calcifying epithelioma of Malherbe, was made
DISCUSSION
Pilomatricoma is a benign appendageal
tumor occurring most commonly on the head and neck of children and adolescents.
Its differentiation most closely resembles that of the hair bulb. Activating
mutations in beta-catenin have been found in some cases, and multiple pilomatricomas
can occur in the setting of Gardner’s syndrome. Clinically, lesions are
solitary, and may have a skin-colored or bluish hue.
Histopathology is significant for the presence of a cystic space with basaloid
cells at the periphery transitioning to eosinophillic “shadow” or
“ ghost” cells centrally. These are anucleate keratinized cells
representing metrical cells. The basaloid cells are monomorphous with prominent
nucleoli. Granulomatous inflammation, fibrosis, and multi-nucleated giant cells
may be found in the stroma at sites of rupture or in long-standing lesions.
Foci of calcification are common.
Treatment is surgical excision. Local recurrence is rare and malignant transformation
has been reported.
REFERENCES
1. Danielson-Cohen A, Lin SJ, Hughes CA, et al. Head and neck pilomatrixoma in children. Arch Otolaryngol Head Neck Surg 127:1481-3,2001.
2. Kaddu S et al. Morphological stages of pilomatricoma. Am J Dermatopathol 18:333, 1996.
3. Sassmannshausen J, Chaffins M: Pilomatrix carcinoma: A report of a case arising from a previously excised pilomatrixoma and a review of the literature. J Am Acad Dermatol 44: 358, 2001.
4. Weedon D: Tumors of cutantous
appendages, in Skin Pathology, New York, Churchill-Livingstons, 1997, p 713.