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Pilomatrixoma—accuracy of clinical diagnosis
Journal of Pediatric Surgery (2006) 41, 1755 – 1758
www.elsevier.com/locate/jpedsurg
Pilomatrixoma—accuracy of clinical diagnosis N. Kumarana, Amir Azmya, Robert Carachia, Peter A.M. Rainea,* Jeanette H. Macfarlaneb, Alan G. Howatsonb a
Department of Paediatric Surgery, Yorkhill Royal Hospital for Sick Children, G3 8SJ Glasgow, UK Department of Paediatric Pathology, Yorkhill Royal Hospital for Sick Children, G3 8SJ Glasgow, UK
b
Index words: Pilomatrixoma; Malherbe’s calcifying epithelioma; Skin neoplasm; Pilomatricoma; Trichomatricoma; Diagnosis
Abstract Background/Purpose: Pilomatrixoma is a common tumor of skin appendages in children. The aim of the study was to assess the accuracy of clinical diagnosis and factors contributing to misdiagnosis. Methods: A retrospective case note review of patients who had pilomatrixoma excised during a 5-year period in a tertiary referral children’s hospital in the UK. Results: From 75 patients, 78 pilomatrixomata were excised. The diagnosis was achieved preoperatively in 46% of patients. Other diagnoses included sebaceous and dermoid cysts, foreign body reaction, calcification in lymph gland, and fat necrosis. Conclusion: Factors contributing to misdiagnosis include cystic lesions with varying consistency, punctum-like appearance, atypical location, and absence of clinically recognizable calcification. Despite close excision, the recurrence rate is low. D 2006 Elsevier Inc. All rights reserved.
In 1880, Malherbe and Chenantais [1] described a benign skin tumor and named it bcalcifying epithelioma.Q Subsequently, the origin from matrix cells of hair follicles was confirmed by histochemical and ultrastructural studies, and the term bpilomatrixomaQ was coined; bpilomatricomaQ and btrichomatricomaQ are alternatives [2-4]. The aim of the study was to assess the accuracy of clinical diagnosis. It was prompted by an index patient—a 12-year-old girl who presented with a 2-year history of a lump in the right earlobe (Fig. 1). The lesion had a cystic consistency and was thought to be an inclusion dermoid because the lobe had been pierced a few months previously. The histological diagnosis of pilomatrixoma was unexpected.
* Corresponding author. Tel.: +44 141 2010289; fax: +44 141 2010865. E-mail address: [email protected] (P.A.M. Raine). 0022-3468/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2006.05.005
1. Methods Pathology records were used to identify patients who had pilomatrixomata excised in a 5-year period (from January 1999 to December 2003). Retrospective case note study sought demographic data, clinical features, pre- and peroperative diagnoses, histological features, and clinical outcome. Results were compared with the literature.
2. Results In 75 patients, 78 pilomatrixomata were detected. Ages ranged from 1.1 to 14.1 years (median, 6.7 years). There was a slight female preponderance (female/male, 8:7). There was 1 patient who had 2 lumps at presentation, and 2 who developed a separate second lesion within the study period. One child had a local recurrence within the study period, but this pilomatrixoma was not included in the analysis.
1756
N. Kumaran et al. diagnosis in 2 (2.6%) and made peroperatively in 5 (6.4%). The histological diagnosis of pilomatrixoma was unexpected in 35 patients (45%). Other preoperative diagnoses included sebaceous cyst (16), dermoid cyst (9), foreign body reaction (2), calcified lymph node (2), fat necrosis, nonspecific cyst, molluscum contagiosum, and cartilage. Two patients presented with abscess requiring initial drainage. One patient with a diagnosis of calcified lymph node of the arm had an evaluation whereby pulmonary tuberculosis was detected. Because the lesion was enlarging and itchy despite successful antimycobacterial therapy, an excision was performed. During the same study period, 11 lesions that were diagnosed clinically as pilomatrixomata turned out to have different histological diagnoses (ie, false positives). They included xanthoma (2), dense inflammation related to a hair follicle (1), dermatofibroma (2), fat necrosis (2), and sebaceous cyst (1). Fig. 1
The earlobe lesion.
Two patients had previous pilomatrixomata excised before the study period; in one, the pilomatrixoma in the study was a local recurrence.
2.1. Clinical features Painless lump was the most common presenting feature (52). Pain and/or mild tenderness was present in 26 patients. A history of recurrent inflammation (13), cosmetic concern (2), anxiety over rapid enlargement (2), and discomfort by catching on clothes (1) or comb (1) was also noted. Tumor size ranged from 3 to 43 mm. Clinical features that contributed to misdiagnosis included cystic consistency (10), punctum-like appearance (5), and history of trauma (3).
2.2. Location The most common sites were the head (mainly face) and neck (73%) and the upper limb (23%) (Fig. 2).
2.6. Treatment One of the facial lesions extruded spontaneously while awaiting surgery (lesion submitted for histology). The other 77 lesions were excised surgically under general anesthesia, often through slightly inflamed skin or with minimal normal surrounding skin to minimize cosmetic problems; all excisions healed satisfactorily.
2.7. Histopathology All the lesions were reported histologically as pilomatrixomata. They exhibited the presence of basaloid cells and/or ghost cells (vide infra). Other common features included stippled calcification in the cytoplasm and foreign body giant cell reaction. Calcification was seen in 72 patients (91%) and bony metaplasia in 2 (2.6%). The pseudocapsule was thin in many cases, and the completeness of excision could not be assured in 43 instances (53%)—this may signify fragmentation at operation or incomplete excision.
2.3. Associated lesions Three patients had associated sebaceous cysts. A patient with trisomy 19 had multiple sebaceous cysts. One child presented with an ulcerating nodular pilomatrixoma from a preexisting sebaceous naevus of Jadassohn located in the scalp [5].
2.4. Imaging A total of 4 patients had ultrasound, and 2 also had plain x-ray. Calcification was seen in all.
2.5. Diagnosis The diagnosis of pilomatrixoma was made preoperatively in 36 instances (46%), included in the differential
Fig. 2
Distribution of location.
Pilomatrixoma—accuracy of clinical diagnosis
1757
3. Discussion Albert Hippolyte Malherbe and J. Chentenais (1880) [1] first described calcifying epithelioma. Their patients’ ages ranged from 9 months to 50 years. Malherbe described the bony metaplasia exhibited by this lesion and contended that it was biologically important because it proved that true bone can form from connective tissue [6]. He considered these lesions as sarcomas because of the connective tissue element [7]. Multiple and recurrent lesions in the same patient coupled with reports of familial incidence have generated much interest in the genetics of this lesion. Activating bcatenin gene mutations are described [8], and the locus of this tumor is mapped to CTNNB1 gene on 3p22-p21.3 [9,10]. Associations are reported between this tumor and disorders such as myotonic dystrophy, Rubinstein-Taybi syndrome, Turner syndrome, Gardner syndrome, xeroderma pigmentosum, and basal cell nevus syndrome [11-13]. One of our patients had trisomy 19 and multiple epidermoid cysts. Clinically, pilomatrixomata are firm to hard nodules attached to the skin and mobile over underlying structures. Head and neck followed by upper extremities are the most frequent distribution [14]. These tumors are most frequent in those younger than 20 years, although presentations throughout adulthood [15] and in the elderly are reported [16]. Our study recorded only a slight female preponderance, but others have recorded a much higher ratio of up to 1.75:1 [17]. The incidence of local recurrence is low, and malignant variants are rare [18]. Complete excision is the treatment of choice. Despite the common occurrence of the lesion, accurate preoperative diagnosis is achieved only in 28.9% to 43% [14,17,19,20]. Skin tethering (interpreted as a punctum), cystic consistency, absence of clinically recognizable calcification, presence of coexistent pathology (adjacent epidermoid cyst, pulmonary tuberculosis), rapid enlargement, and a history of trauma contributed to this low rate. Sebaceous cysts are very uncommon in prepubertal children and should not form part of the differential diagnosis. Preoperative imaging has little to offer except in deep locations. Microscopically, pilomatrixomata are usually sharply demarcated with a connective tissue capsule. They exhibit a morphological progression according to the age of the lesion. Basaloid cells are matrix cells that fail to differentiate into a hair follicle. The lesion usually comprises islands where the basophilic dbasaloid cellsT containing sparse cytoplasm, hyperchromatic nuclei, plentiful mitoses, and indistinct cell border are predominantly arranged in the periphery (Fig. 3). When these cells mature and keratinise and lose nuclei by karyolysis, they form shadow (dghostT) cells that are predominantly eosinophilic and tend to lie in the center of the cell islands. Basaloid cells evoke a foreign body response with giant cell formation and dystrophic calcification. Frank bony metaplasia including foci of
Fig. 3 Histology of the lesion from Fig. 1 demonstrating hyperchromatic nuclei of basaloid cells (heavy arrow) and fine stippled calcification (light arrow).
extramedullary erythropoeisis have been noted. Bone morphogenic protein, noted in the shadow cells, may play a causative role in this. Hemosiderin and melanin deposition can occur [21]. Because high mitotic activity is a feature of the basaloid cells, this finding in itself does not lead to a diagnosis of malignancy, but presence of other features such as cytological atypia, local aggressive behavior, vascular invasion, and infiltrative basaloid nodules leads to a diagnosis of the rare pilomatrix carcinoma. Pilomatrixomata do not regress or disappear, but transdermal elimination has been reported as dperforating pilomatricoma,T and this was noted in one of our patients [22]. Close excision for cosmetic reasons may raise questions about completeness of removal (53%) in our series, but the recurrence rate is very low (1.3%).
3.1. Conclusion Factors contributing to misdiagnosis of pilomatrixoma include cystic lesions with varying consistency, punctumlike appearance, atypical location, and absence of clinically recognizable calcification. Despite close excision, the recurrence rate is low.
References [1] Malherbe A, Chenantais J. Note sur l’e´pitheliome calcifie´ des glandes se´bace´es. Prog Med 1880;8:826 - 8. [2] Forbis Jr R, Helwig EB. Pilomatrixoma (calcifying epithelioma). Arch Dermatol 1961;83:606 - 18. [3] Migirov L, Fridman E, Talmi YP. Pilomatrixoma of the retroauricular area and arm. J Pediatr Surg 2002;37(8):E20. [4] Hashimoto K, Prince C, Kato I, et al. Rippled-pattern trichomatricoma. Histological, immunohistochemical and ultrastructural studies of an immature hair matrix tumor. J Cutan Pathol 1989; 16(1):19 - 30. [5] Cribier B, Scrivener Y, Grosshans E. Tumors arising in nevus sebaceous: a study of 596 cases. J Am Acad Dermatol 2000;42: 263 - 8.
1758 [6] Steffan C. Albert Hippolyte Malherbe: the man behind the eponym. Am J Dermatopathol 1989;11:182 - 4. [7] Malherbe A, Malherbe H. Recherches sur le sarcoma. Paris, Masson et Cie, E´diteurs, Libraires de l’Acade´mie e Me´decine, 1904. [8] Chan EF. Pilomatricomas contain activating mutations in b-catenin. J Am Acad Dermatol 2000;43:701. [9] Chan EF, Gat U, McNiff JM, et al. A common human skin tumour is caused by activating mutations in beta-catenin. Nat Genet 1999;21(4): 410 - 3. [10] Online Mendelian Inheritance in Man, OMIM (TM). Johns Hopkins University, Baltimore, MD. MIM Number: #132600: 2/24/2003: World Wide Web URL: www.ncbi.nlm.nih.gov/entrez/dispomim. cgi?id=132600. [11] Geh JL, Moss AL. Multiple pilomatrixomata and myotonic dystrophy: a familial association. Br J Plast Surg 1999;52(2):43 - 5. [12] Cambiaghi S, Ermacora E, Brusasco A, et al. Multiple pilomatricomas in Rubinstein-Taybi syndrome: a case report. Pediatr Dermatol 1994;11(1):21 - 5. [13] Noguchi H, Kayashima K, Nishiyama S, et al. Two cases of pilomatrixoma in Turner’s syndrome. Dermatology 1999;199(4): 338 - 40.
N. Kumaran et al. [14] Jacobsen AS, Bowen J, Bruce J, et al. The calcifying epithelioma of Malherbe in children: a 15 year experience. Pediatr Surg Int 1995;10:44 - 5. [15] Thomas RW, Perkins JA, Ruegemer JL, et al. Surgical excision of pilomatrixoma of the head and neck: a retrospective review of 26 cases. Ear Nose Throat J 1999;78(8):541, 544-6, 548. [16] Behnke N, Schulte K, Ruzicka T, et al. Pilomatricoma in the elderly individuals. Dermatology 1998;197:391 - 3. [17] Pirouzmanesh A, Reinisch JF, Gonzlez-Gomez I, et al. Pilomatrixoma: a review of 346 cases. Plast Reconstr Surg 2003;112(7):1785 - 9. [18] Rao J, Lin A. Pilomatrixoma 27 Feb 2002 update. World Wide Web URL: www.emedicine.com/derm/topic329.htm. [19] Wells NJ, Blair GK, Magee JF, et al. Pilomatrixoma: a common, benign childhood skin tumour. Can J Surg 1994;37:483 - 6. [20] Colver GB, Buxton PK. Pilomatrixoma an elusive diagnosis. Int J Dermatol 1988;27:177 - 8. [21] Weedon D. Tumors of cutaneous appendages. In: Weedon D, Strutton G, editors. Skin pathology. 2nd ed. Oxford, UK: Elsevier Science Ltd., 2002. p. 859 - 916. [22] Alli N, Gungor E, Artuz F. Perforating pilomatricoma. J Am Acad Dermatol 1996;35(1):116 - 8.
www.elsevier.com/locate/jpedsurg
Pilomatrixoma—accuracy of clinical diagnosis N. Kumarana, Amir Azmya, Robert Carachia, Peter A.M. Rainea,* Jeanette H. Macfarlaneb, Alan G. Howatsonb a
Department of Paediatric Surgery, Yorkhill Royal Hospital for Sick Children, G3 8SJ Glasgow, UK Department of Paediatric Pathology, Yorkhill Royal Hospital for Sick Children, G3 8SJ Glasgow, UK
b
Index words: Pilomatrixoma; Malherbe’s calcifying epithelioma; Skin neoplasm; Pilomatricoma; Trichomatricoma; Diagnosis
Abstract Background/Purpose: Pilomatrixoma is a common tumor of skin appendages in children. The aim of the study was to assess the accuracy of clinical diagnosis and factors contributing to misdiagnosis. Methods: A retrospective case note review of patients who had pilomatrixoma excised during a 5-year period in a tertiary referral children’s hospital in the UK. Results: From 75 patients, 78 pilomatrixomata were excised. The diagnosis was achieved preoperatively in 46% of patients. Other diagnoses included sebaceous and dermoid cysts, foreign body reaction, calcification in lymph gland, and fat necrosis. Conclusion: Factors contributing to misdiagnosis include cystic lesions with varying consistency, punctum-like appearance, atypical location, and absence of clinically recognizable calcification. Despite close excision, the recurrence rate is low. D 2006 Elsevier Inc. All rights reserved.
In 1880, Malherbe and Chenantais [1] described a benign skin tumor and named it bcalcifying epithelioma.Q Subsequently, the origin from matrix cells of hair follicles was confirmed by histochemical and ultrastructural studies, and the term bpilomatrixomaQ was coined; bpilomatricomaQ and btrichomatricomaQ are alternatives [2-4]. The aim of the study was to assess the accuracy of clinical diagnosis. It was prompted by an index patient—a 12-year-old girl who presented with a 2-year history of a lump in the right earlobe (Fig. 1). The lesion had a cystic consistency and was thought to be an inclusion dermoid because the lobe had been pierced a few months previously. The histological diagnosis of pilomatrixoma was unexpected.
* Corresponding author. Tel.: +44 141 2010289; fax: +44 141 2010865. E-mail address: [email protected] (P.A.M. Raine). 0022-3468/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2006.05.005
1. Methods Pathology records were used to identify patients who had pilomatrixomata excised in a 5-year period (from January 1999 to December 2003). Retrospective case note study sought demographic data, clinical features, pre- and peroperative diagnoses, histological features, and clinical outcome. Results were compared with the literature.
2. Results In 75 patients, 78 pilomatrixomata were detected. Ages ranged from 1.1 to 14.1 years (median, 6.7 years). There was a slight female preponderance (female/male, 8:7). There was 1 patient who had 2 lumps at presentation, and 2 who developed a separate second lesion within the study period. One child had a local recurrence within the study period, but this pilomatrixoma was not included in the analysis.
1756
N. Kumaran et al. diagnosis in 2 (2.6%) and made peroperatively in 5 (6.4%). The histological diagnosis of pilomatrixoma was unexpected in 35 patients (45%). Other preoperative diagnoses included sebaceous cyst (16), dermoid cyst (9), foreign body reaction (2), calcified lymph node (2), fat necrosis, nonspecific cyst, molluscum contagiosum, and cartilage. Two patients presented with abscess requiring initial drainage. One patient with a diagnosis of calcified lymph node of the arm had an evaluation whereby pulmonary tuberculosis was detected. Because the lesion was enlarging and itchy despite successful antimycobacterial therapy, an excision was performed. During the same study period, 11 lesions that were diagnosed clinically as pilomatrixomata turned out to have different histological diagnoses (ie, false positives). They included xanthoma (2), dense inflammation related to a hair follicle (1), dermatofibroma (2), fat necrosis (2), and sebaceous cyst (1). Fig. 1
The earlobe lesion.
Two patients had previous pilomatrixomata excised before the study period; in one, the pilomatrixoma in the study was a local recurrence.
2.1. Clinical features Painless lump was the most common presenting feature (52). Pain and/or mild tenderness was present in 26 patients. A history of recurrent inflammation (13), cosmetic concern (2), anxiety over rapid enlargement (2), and discomfort by catching on clothes (1) or comb (1) was also noted. Tumor size ranged from 3 to 43 mm. Clinical features that contributed to misdiagnosis included cystic consistency (10), punctum-like appearance (5), and history of trauma (3).
2.2. Location The most common sites were the head (mainly face) and neck (73%) and the upper limb (23%) (Fig. 2).
2.6. Treatment One of the facial lesions extruded spontaneously while awaiting surgery (lesion submitted for histology). The other 77 lesions were excised surgically under general anesthesia, often through slightly inflamed skin or with minimal normal surrounding skin to minimize cosmetic problems; all excisions healed satisfactorily.
2.7. Histopathology All the lesions were reported histologically as pilomatrixomata. They exhibited the presence of basaloid cells and/or ghost cells (vide infra). Other common features included stippled calcification in the cytoplasm and foreign body giant cell reaction. Calcification was seen in 72 patients (91%) and bony metaplasia in 2 (2.6%). The pseudocapsule was thin in many cases, and the completeness of excision could not be assured in 43 instances (53%)—this may signify fragmentation at operation or incomplete excision.
2.3. Associated lesions Three patients had associated sebaceous cysts. A patient with trisomy 19 had multiple sebaceous cysts. One child presented with an ulcerating nodular pilomatrixoma from a preexisting sebaceous naevus of Jadassohn located in the scalp [5].
2.4. Imaging A total of 4 patients had ultrasound, and 2 also had plain x-ray. Calcification was seen in all.
2.5. Diagnosis The diagnosis of pilomatrixoma was made preoperatively in 36 instances (46%), included in the differential
Fig. 2
Distribution of location.
Pilomatrixoma—accuracy of clinical diagnosis
1757
3. Discussion Albert Hippolyte Malherbe and J. Chentenais (1880) [1] first described calcifying epithelioma. Their patients’ ages ranged from 9 months to 50 years. Malherbe described the bony metaplasia exhibited by this lesion and contended that it was biologically important because it proved that true bone can form from connective tissue [6]. He considered these lesions as sarcomas because of the connective tissue element [7]. Multiple and recurrent lesions in the same patient coupled with reports of familial incidence have generated much interest in the genetics of this lesion. Activating bcatenin gene mutations are described [8], and the locus of this tumor is mapped to CTNNB1 gene on 3p22-p21.3 [9,10]. Associations are reported between this tumor and disorders such as myotonic dystrophy, Rubinstein-Taybi syndrome, Turner syndrome, Gardner syndrome, xeroderma pigmentosum, and basal cell nevus syndrome [11-13]. One of our patients had trisomy 19 and multiple epidermoid cysts. Clinically, pilomatrixomata are firm to hard nodules attached to the skin and mobile over underlying structures. Head and neck followed by upper extremities are the most frequent distribution [14]. These tumors are most frequent in those younger than 20 years, although presentations throughout adulthood [15] and in the elderly are reported [16]. Our study recorded only a slight female preponderance, but others have recorded a much higher ratio of up to 1.75:1 [17]. The incidence of local recurrence is low, and malignant variants are rare [18]. Complete excision is the treatment of choice. Despite the common occurrence of the lesion, accurate preoperative diagnosis is achieved only in 28.9% to 43% [14,17,19,20]. Skin tethering (interpreted as a punctum), cystic consistency, absence of clinically recognizable calcification, presence of coexistent pathology (adjacent epidermoid cyst, pulmonary tuberculosis), rapid enlargement, and a history of trauma contributed to this low rate. Sebaceous cysts are very uncommon in prepubertal children and should not form part of the differential diagnosis. Preoperative imaging has little to offer except in deep locations. Microscopically, pilomatrixomata are usually sharply demarcated with a connective tissue capsule. They exhibit a morphological progression according to the age of the lesion. Basaloid cells are matrix cells that fail to differentiate into a hair follicle. The lesion usually comprises islands where the basophilic dbasaloid cellsT containing sparse cytoplasm, hyperchromatic nuclei, plentiful mitoses, and indistinct cell border are predominantly arranged in the periphery (Fig. 3). When these cells mature and keratinise and lose nuclei by karyolysis, they form shadow (dghostT) cells that are predominantly eosinophilic and tend to lie in the center of the cell islands. Basaloid cells evoke a foreign body response with giant cell formation and dystrophic calcification. Frank bony metaplasia including foci of
Fig. 3 Histology of the lesion from Fig. 1 demonstrating hyperchromatic nuclei of basaloid cells (heavy arrow) and fine stippled calcification (light arrow).
extramedullary erythropoeisis have been noted. Bone morphogenic protein, noted in the shadow cells, may play a causative role in this. Hemosiderin and melanin deposition can occur [21]. Because high mitotic activity is a feature of the basaloid cells, this finding in itself does not lead to a diagnosis of malignancy, but presence of other features such as cytological atypia, local aggressive behavior, vascular invasion, and infiltrative basaloid nodules leads to a diagnosis of the rare pilomatrix carcinoma. Pilomatrixomata do not regress or disappear, but transdermal elimination has been reported as dperforating pilomatricoma,T and this was noted in one of our patients [22]. Close excision for cosmetic reasons may raise questions about completeness of removal (53%) in our series, but the recurrence rate is very low (1.3%).
3.1. Conclusion Factors contributing to misdiagnosis of pilomatrixoma include cystic lesions with varying consistency, punctumlike appearance, atypical location, and absence of clinically recognizable calcification. Despite close excision, the recurrence rate is low.
References [1] Malherbe A, Chenantais J. Note sur l’e´pitheliome calcifie´ des glandes se´bace´es. Prog Med 1880;8:826 - 8. [2] Forbis Jr R, Helwig EB. Pilomatrixoma (calcifying epithelioma). Arch Dermatol 1961;83:606 - 18. [3] Migirov L, Fridman E, Talmi YP. Pilomatrixoma of the retroauricular area and arm. J Pediatr Surg 2002;37(8):E20. [4] Hashimoto K, Prince C, Kato I, et al. Rippled-pattern trichomatricoma. Histological, immunohistochemical and ultrastructural studies of an immature hair matrix tumor. J Cutan Pathol 1989; 16(1):19 - 30. [5] Cribier B, Scrivener Y, Grosshans E. Tumors arising in nevus sebaceous: a study of 596 cases. J Am Acad Dermatol 2000;42: 263 - 8.
1758 [6] Steffan C. Albert Hippolyte Malherbe: the man behind the eponym. Am J Dermatopathol 1989;11:182 - 4. [7] Malherbe A, Malherbe H. Recherches sur le sarcoma. Paris, Masson et Cie, E´diteurs, Libraires de l’Acade´mie e Me´decine, 1904. [8] Chan EF. Pilomatricomas contain activating mutations in b-catenin. J Am Acad Dermatol 2000;43:701. [9] Chan EF, Gat U, McNiff JM, et al. A common human skin tumour is caused by activating mutations in beta-catenin. Nat Genet 1999;21(4): 410 - 3. [10] Online Mendelian Inheritance in Man, OMIM (TM). Johns Hopkins University, Baltimore, MD. MIM Number: #132600: 2/24/2003: World Wide Web URL: www.ncbi.nlm.nih.gov/entrez/dispomim. cgi?id=132600. [11] Geh JL, Moss AL. Multiple pilomatrixomata and myotonic dystrophy: a familial association. Br J Plast Surg 1999;52(2):43 - 5. [12] Cambiaghi S, Ermacora E, Brusasco A, et al. Multiple pilomatricomas in Rubinstein-Taybi syndrome: a case report. Pediatr Dermatol 1994;11(1):21 - 5. [13] Noguchi H, Kayashima K, Nishiyama S, et al. Two cases of pilomatrixoma in Turner’s syndrome. Dermatology 1999;199(4): 338 - 40.
N. Kumaran et al. [14] Jacobsen AS, Bowen J, Bruce J, et al. The calcifying epithelioma of Malherbe in children: a 15 year experience. Pediatr Surg Int 1995;10:44 - 5. [15] Thomas RW, Perkins JA, Ruegemer JL, et al. Surgical excision of pilomatrixoma of the head and neck: a retrospective review of 26 cases. Ear Nose Throat J 1999;78(8):541, 544-6, 548. [16] Behnke N, Schulte K, Ruzicka T, et al. Pilomatricoma in the elderly individuals. Dermatology 1998;197:391 - 3. [17] Pirouzmanesh A, Reinisch JF, Gonzlez-Gomez I, et al. Pilomatrixoma: a review of 346 cases. Plast Reconstr Surg 2003;112(7):1785 - 9. [18] Rao J, Lin A. Pilomatrixoma 27 Feb 2002 update. World Wide Web URL: www.emedicine.com/derm/topic329.htm. [19] Wells NJ, Blair GK, Magee JF, et al. Pilomatrixoma: a common, benign childhood skin tumour. Can J Surg 1994;37:483 - 6. [20] Colver GB, Buxton PK. Pilomatrixoma an elusive diagnosis. Int J Dermatol 1988;27:177 - 8. [21] Weedon D. Tumors of cutaneous appendages. In: Weedon D, Strutton G, editors. Skin pathology. 2nd ed. Oxford, UK: Elsevier Science Ltd., 2002. p. 859 - 916. [22] Alli N, Gungor E, Artuz F. Perforating pilomatricoma. J Am Acad Dermatol 1996;35(1):116 - 8.