Pilomatricoma, besides known as pilomatrixoma or calcifying epithelioma of Malherbe, is a benign skin tumour that arises from hair follicle matrix cells ( 1, 2 ) . Pilomatricomas are most normally located in the caput and cervix and normally occur in the first two decennaries of life ( 2, 3 ) . The usual presentation is that of a difficult, normally lone, nomadic, slow turning mass of the corium or hypodermic tissue that may do ulceration or a stain of the superficial tegument ( 1, 4 ) .

Histopathologically, pilomatricomas are characterized by the presence of eosinophilic keratinized cells, called shadow or shade cells, and basalloid cells ( 1, 2, 4 ) . Calcification is a common histopathologic characteristic of pilomatricoma while ossification is rare ( 1 ) . The purpose of this instance study is to show a rare instance of a pilomatricoma of the arm in a 33 twelvemonth old female that was characterized by extended ossification and to familiarise the general sawbones with this, known to diagnosticians and skin doctors, clinical entity.


A 33 twelvemonth old female, with a free medical history, presented to our surgical section because of an symptomless mass on her left arm that she had foremost noticed about half a twelvemonth ago. Clinical scrutiny revealed a lone, difficult, nomadic, good limited nodule with the superficial tegument being wholly healthy, that was considered a foreign organic structure reaction.

The tumour which measured 1×0,7×0,6 centimeter, was removed with a spindle-shaped surgical deletion. Macroscopic scrutiny revealed a nodular tumour located in the deeper beds of the corium adjacent to the hypodermic tissue. The overlying tegument was healthy ( Fig 1 ) . Microscopically it consisted of solid islands of shadow with extended ossification. Even the usual nests of little basaloid cells were absent ( Fig 2 ) . The diagnosing of pilomatricoma with extended ossification was established.

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Pilomatricoma is a tumour of hair matrix that is about ever benign ( 2 ) with less than 20 instances of malignant transmutation holding been reported in the literature ( 3 ) . The most common anatomical location is the caput and cervix part ( 1-5 ) , with 40 -77 % of all instances happening in that country, followed in frequence by the upper appendages, the bole and the lower appendages ( 3 ) . Pilomatricomas most frequently present before the age of 20 old ages, and particularly among kids, with a male to female ratio of approximately 1 to 1,5-1,75 ( 5 ) ( 1 ) . The clinical presentation is that of a house or hard, Mobile, good demarcated nodule, either profoundly hypodermic and unseeable or superficial with possible eroding of the tegument ( 1, 4 ) . Pilomatricomas by and large develop as a lone lesion although multiple pilomatricomas have besides been reported ( 1 ) . In our instance, the preoperative diagnosing was wrong as the presence of a nodule in the arm of a 33 twelvemonth old adult female is non typical of pilomatricoma

Histopathologically, pilomatricomas are composed by unvarying basalloid cells, with outstanding karyons and eosinophilic keratinized anucleated cells, called shadow cells ( 1, 2, 4 ) . Basaloid cells are normally less in figure than shadow cells, and sometimes there are no basaloid cells. Shadow cells are identified by the lost karyon, which leaves a cardinal unstained country and are characteristic of pilomatricoma. They are found towards the centre of the tumour and may organize multitudes, coils or tonss. Calcification is a common characteristic, while dystrophic ossification or melanin pigmentation is rare. ( 1, 2, 4 )

Based upon histopathological findings Kaddu et Al ( 5 ) propose that pilomatricomas may be categorized into four distinguishable morphological and chronological phases: early, to the full developed, early regressive and late regressive, which show the natural history of pilomatricoma. Early phase pilomatricomas are little and cystic and lined by a basaloid epithelial tissue and incorporating shadow cells. Fully developed pilomatricomas are big, cystic and egg-shaped lined by a basaloid epithelial tissue and incorporating shadow cells. Early regressive pilomatricomas are characterized by basaloid cells, without though evident basaloid epithelial tissue, inflammatory infiltration and shadow or multinucleated elephantine cells. Late regressive pilomatricomas have no epithelial constituent, contain legion shadow cells but no basaloid cells, have small or no inflammatory infiltrate and may show calcification and ossification ( 5 ) . In the present instance the pilomatricoma was considered to be a late regressive pilomatricoma.

Differential diagnosing of pilomatricoma include greasy, trichilemmal, dermoid and epidermoid cyst, calcified lymph node, metaplastic bone formation, foreign organic structure granuloma, calcified haematoma, haemangioma, cutaneal osteoma, osteochondroma, trichoepithelioma and basal cell epithelioma ( 1, 3, 6 ) . The diagnosing can by and large be made with a clinical scrutiny but requires careful scrutiny and a high index of intuition ( 1, 3 ) . Fine needle aspiration can help the diagnosing ( 2, 3 ) .

Recommended intervention of pilomatricoma is ideally by scratch and curettement ( 4 ) but can besides be managed by surgical deletion ( 4, 6 ) . The return rate of pilomatricoma is really low following complete surgical deletion ( 1, 6 ) .


  1. Lan MY, Lan MC, Ho CY, Li WY, Lin CZ. Pilomatricoma of the caput and cervix: a retrospective reappraisal of 179 instances. Arch Otolaryngol Head Neck Surg. 2003 ; 129:1327-30.
  2. Wang J, Cobb CJ, Martin SE, Venegas R, Wu N, Greaves TS. Pilomatrixoma: clinicopathologic survey of 51 instances with accent on cytologic characteristics. Diagn Cytopathol. 2002 ; 27:167-72.
  3. Kaddu S, Soyer HP, H & A ; ouml ; deciliter S, Kerl H. Morphological phases of pilomatricoma. Am J Dermatopathol. 1996 ; 18:333-8.
  4. Pirouzmanesh A, Reinisch JF, Gonzalez-Gomez I, Smith EM, Meara JG. Pilomatrixoma: a reappraisal of 346 instances. Plast Reconstr Surg. 2003 ; 112:1784-9.
  5. Julian CG, Bowers PW. A clinical reappraisal of 209 pilomatricomas. J Am Acad Dermatol. 1998 ; 39:191-5.
  6. Yoshimura Y, Obara S, Mikami T, Matsuda S. Calcifying epithelioma ( pilomatrixoma ) of the caput and cervix: analysis of 37 instances. Br J Oral Maxillofac Surg. 1997 ; 35:429-32.


  • FIGURE 1: Hematoxylin – eosin discoloration demoing a tumour located in the deeper corium with normal overlying tegument ( ten 20 )
  • Figure 2: Hematoxylin – eosin discoloration of the tumour demoing islands of shadow cells and countries of extended ossification ( A: ten 100, B: ten 200 )

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