Giant intramuscular calcifying aponeurotic fibroma of gluteus maximus: case report

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1 Annals of Tropical Paediatrics (2010) 30, Giant intramuscular calcifying aponeurotic fibroma of gluteus maximus: case report S. ARORA, D. SABAT, S. K. ARORA*, V. KUMAR & R. K. SARAN { Department of Orthopaedic Surgery, Maulana Azad Medical College & Associated Lok Nayak Hospital, New Delhi, *Department of Paediatrics, University College of Medical Sciences & Associated Guru Teg Bahadur Hospital, Delhi and { Department of Pathology, G. B. Pant Hospital, New Delhi, India (Accepted April 2010) Annals of Tropical Paediatrics atp0314.3d 21/7/10 21:58:30 Abstract Calcifying aponeurotic fibroma (CAF) is a rare soft tissue tumour which occurs mainly in children and adolescents. It usually involves the distal portion of the extremities, i.e. the hands and feet. A 2-year-old child with a large CAF is presented. The case was unusual in view of its large size ( cm), dense calcification in such a young child, and because it was situated in the substance of gluteus maximus muscle. There has been no recurrence at 3-year follow-up. Introduction Calcifying aponeurotic fibroma (CAF) is a rare, well differentiated soft tissue fibrous tumour with a predilection for the acral aspects of the extremities in children and adolescents. 1 It is locally aggressive and may recur after surgical removal. 1 Very few detailed cases of this condition are on record. We describe a large CAF in a 2- year-old child. Case Report A 2-year-old firstborn boy presented to the Department of Orthopaedic Surgery, Maulana Azad Medical College & associated Lok Nayak Hospital, New Delhi with a 1-year history of a gradually enlarging swelling in the right gluteal region. It was associated with pain only on sitting. There Reprint requests to: Dr Sumit Arora, c/o Mr Sham Khanna, 2/2, Vijay Nagar, Delhi , India. mamc_309@yahoo.co.in was no history of trauma, fever, weight loss, bone pain, drug ingestion, local intramuscular injections or preceding viral illnesses. There was no past history of any haematological or other chronic illness or similar lump in any other part of the body. His birth history was unremarkable. General physical examination findings were normal. There was a firm, non-tender mass, 1267 cm, in the right gluteal region (Fig. 1). The margins were ill defined but overlying skin and underlying tissue were normal. The lump was mobile and the surface appeared lobulated. There was no lymphadenopathy. Results of haematological investigations were within the normal range. Radiographs of the pelvis and hip joints showed multiple foci of dense calcification in the right gluteal region (Fig. 2). Sonographic examination suggested the presence of a solid, lobulated, non-cystic soft tissue mass measuring cm posterior to the right hip joint with internal punctate hyper-echoic foci, suggestive of calcification. MRI with T1- and T2-weighted images demonstrated a well circumscribed soft tissue tumour in the # W. S. Maney & Son Ltd 2010 DOI: / X

2 260 S. Arora et al. ONLINE COLOUR ONLY FIG. 1. A large swelling in the right gluteal region. Annals of Tropical Paediatrics atp0314.3d 21/7/10 21:58:45 FIG. 2. AP radiographs of pelvis and hip joints showing a large area of fluffy calcification (arrow) with distinct margins in the right gluteal region. substance of gluteus maximus muscle with areas of calcification (Fig. 3). Excisional biopsy was undertaken. On exploration, an encapsulated mass was found in the substance of gluteus maximus with no infiltration in the surrounding region. The yellowish-white mass which had good vascularity was excised en bloc and measured cm in its greatest dimensions. The surface was lobulated and had a firm consistency. It was gritty to cut and the surface was homogenous without areas of necrosis or haemorrhage (Fig. 4). Histopathological examination with haematoxylin and eosin staining demonstrated a well circumscribed nodular lesion consisting of spindled fibroblasts arranged in a pallisading and zig-zag pattern. There were numerous calcific spherules and focal areas of chronic inflammatory cell infiltration with a background of densely collagenous stroma. There were no signs of mitotic activity or nuclear atypia. A diagnosis of CAF was made. At 3-year follow-up, the patient remains asymptomatic with no recurrence. Written, informed consent was obtained from the parents authorising radiological and photographic documentation and they were also informed that data

3 Giant calcifying aponeurotic fibroma 261 Annals of Tropical Paediatrics atp0314.3d 21/7/10 21:58:48 FIG. 3. concerning the case might be submitted for publication. Discussion MR images demonstrating large soft tissue mass in the substance of right gluteus maximus (arrow). In 1953, Keasbey first described this rare entity in the hand or foot of four children (aged 2 to 9 years) and termed it juvenile aponeurotic fibroma. 1 In 1964, Lichtenstein & Goldman termed it cartilage analogue of fibromatosis. 2 In 1973, Iwasaki & Enjoji coined the term calcifying aponeurotic fibroma (CAF) after it had been shown to be present in the adolescents and adults. 3 It is more common in males and usual manifestats within 1st 2 decades of life. 4 The predominant locations are palm, foot, wrist, elbow, knee and forearm. 5 7 It is usually found superficially in subcutaneous planes involving fat, fascia, aponeurosis and tendons. The usual clinical presentation is a slowly growing, firm, mobile mass in the distal aspects of the extremities in adolescents. It has been reported also in the lower back and thigh. 8 Extensive search of the English-language medical literature did not find a similar case of CAF in the gluteus maximus muscle. Radiographic features are usually inconclusive. Usually, radiographs only show fluffy opacities in the substance of the tumour, which may with time become areas of dense calcification. Multiple dense foci of calcification involving a large area in the right gluteal region in a 2-year-old (this case) may be considered an atypical manifestation of CAF. Sonographic examination may be useful to detect areas of calcification and to exclude causes of cystic lesions. CT may be helpful in detecting areas of calcification and in cases with osseous involvement. Osseous involvement (hand, especially phalanges) in CAF has rarely been reported in the literature. 9,10 CT may be of great value in differentiating it from parosteal chondroma or panniculitis ossificans. 4,7 MRI scan shows soft tissue involvement of the tumour and is considered essential in pre-operative planning. 10 Differential diagnosis of CAF depends upon the patient s age at presentation, the location of the tumour, osseous involvement

4 262 S. Arora et al. ONLINE COLOUR ONLY Annals of Tropical Paediatrics atp0314.3d 21/7/10 21:58:49 FIG. 4. Excisional biopsy specimen of the tumour showing a yellowish-white lobulated mass with good vascularity measuring cm. and degree of calcification. Clinico-radiologically, it may be confused in a young child with inflammatory myofibroblastic tumours, calcifying fibrous pseudotumour, fibrous hamartoma of infancy, diffuse infantile fibromatosis, nodular fasciitis and infantile fibrosarcoma. 4,8,10 It is important to distinguish CAF from other conditions by histopathological examination and, if necessary, by immuno-histochemistry. 3,8 On macroscopic examination, CAF is a rubbery, firm, greyish white mass, usually between 1 and 5 cm in size. 4,8 It is commonly adherent to dense fibrous connective tissue (tendons, fascia, periosteum, etc.). When cutting the specimen, focal punctuate areas of calcification may give a gritty sensation. Microscopy shows spindled fibroblasts with a fascicular pattern (usually around the calcification) containing indistinctly outlined cytoplasm and a round-toovoid nucleus. Epithelioid mesenchymal cells and chondroid foci are usually present against a background of densely collagenous stroma. 1,2 Nuclear atypia is not found but occasional mitoses may be detected. In the initial stages, there might be no calcification; it is more pronounced in older children and adolescents. In CAF, immuno-staining is usually positive with vimentin, CD99, CD68 and S100; has variable results with muscle-specific actin and smooth muscle actin, CD34, CD57, EMA (epithelial membrane antigen) and PR (progesterone receptor); and is negative with ER (oestrogen receptor), desmin and cytokeratin. 8 In this

5 Annals of Tropical Paediatrics atp0314.3d 21/7/10 21:58:52 case, detailed immuno-staining of the specimen was not performed because the parents were unable to afford it. The unusual features of CAF in this case were the young age, the large size and the heavily calcified tumour within the gluteus maximus muscle. Acknowledgment We should like to thank Drs Reema Bhardwaj and Vikas Bhardwaj for their invaluable opinion of the pathology and review of the literature, respectively. References 1 Keasbey LE. Juvenile aponeurotic fibroma (calcifying fibroma). A distinctive tumor arrising in the palms and soles of young children. Cancer 1953; 6: Lichtenstein L, Goldman RL. The cartilage analogue of fibromatosis. A reinterpretation of the Giant calcifying aponeurotic fibroma 263 condition called juvenile aponeurotic fibroma. Cancer 1964; 17: Iwasaki H, Enjoji M. Calcifying aponeurotic fibroma (Japanese). Fukuoka Aeta Med 1973; 64:52. 4 Enzinger FM, Weiss SW. Fibrous tumours of infancy and childhood. In: Enzinger FM, Weiss SW, eds Soft Tissue Tumours, 3rd edn. St Louis: CV Mosby, 1995; De Simone RS, Zielinski CJ. Calcifying aponeurotic fibroma of the hand. A case report. J Bone Joint Surg (Am) 2001; 83: Keller RB, Baez-Giangreco A. Juvenile aponeurotic fibroma: report of three cases and a review of the literature. Clin Orthop 1975; 106: Sferopoulos NK, Kotakidou R. Calcifying aponeurotic fibroma: a report of three cases. Acta Orthop Belg 2001; 67: Fetsch JF, Miettinen M. Calcifying aponeurotic fibroma: a clinicopathologic study of 22 cases arising in uncommon sites. Hum Pathol 1998; 29: Karasick D, O Hara AE. Juvenile aponeurotic fibroma. A review and a report of a case with osseous involvement. Radiology 1977; 123: Choi S-J, Ahn JH, Kang G, et al. Calcifying aponeurotic fibroma with osseous involvement of the finger: a case report with radiologic and US findings. Korean J Radiol 2008; 9:91 3.