130 J. Cranio-Max.-Fac. Surg. 16 (1988)

J. Cranio-Max.-Fac.'Surg. 16 (1988) 130-135 © Georg Thieme Verlag Stuttgart • New York

Juvenile Fibromatosis Nicholas Zachariades, Stavros Papanicolaou

"St. Sophie's" Children's Hospital (Consultant: N. Zachariades, D.D.S, M.D.), Oral and Maxillofacial Department (Head: N. Zachariades, D. D. S., M. D.) "Apostle Paul's" Accidents Hospital and Dept. of Oral Pathology (Head: A. Angelopoulos, D. D. S., Ph.D.), Dental School, National University, Athens, Greece

Submitted 11 .2 . 1986; accepted 3 .6 . 1987

Summary

Fibromatosis is an aggressive, non-metastasizing dis- ease characterized by a neoplastic proliferation of fib- roblasrs, that rarely involves bone and lies on the bor- derline between benign and malignant tumours. We report three new cases of this rare entity.

Key-Words

Fibromatosis - Connective tissue t u m o u r s - Aggres- sive neoplasms

Introduction

Fibromatosis is an aggressive, infiltrative, non-metastasiz- ing disease that was first reported by Stout in 1954. The aetiology and pathogenesis remain unknown (Shafer et al., 1974; Peede and Epker,1977). These lesions constitute a group whose general pattern of behaviour is characterized by a neoplastic proliferation of fibroblasts which infiltrate and replace soft tissues (Lucas, 1976; Peede and Epker, 1977; Henefer et al., 1978). Such lesions as nodular fasc- itis, aggressive fibromatosis, proliferative myositis, fibrous histiocytoma (fibroxanthoma), atypical fibroxanthoma, desmoplastic fibroma, fibromatosis colli, palmar and plan- tar fibromatosis, juvenile fibromatosis, juvenile aponeuro- tic fibroma, cicatrical fibromatosis, keloid, nasopharyngeal fibroma and hereditary gingival fibromatosis are included (Shafer et al., 1974; Henefer et al., 1978; Melrose and Abrams, 1980; Rodu et al., 1981; Geist et al., 1985; Ya- mane et al., 1986). It is possible that some of these named entities are simply synonyms, as used by various authors. It is not clear whether this broad group of tumours is char- acterized by anything more than a basic pattern of similar histology and our inability to comprehend their rather de- finite patterns of behaviour. For instance, while some in- vestigators (Freedman et al., 1978) believe that fibromato- sis and desmoplastic fibroma may be used interchangeably, others (Melrose and Abrams, 1980) disagree. According to some (Henefer et al., 1978), juvenile fibromatosis arises in soft tissues adjacent to bone, while desmoplastic fibroma arises centrally and expands bone.While some authors use the terms juvenile fibromatosis and aggressive fibromato- sis interchangeably, others prefer to differentiate between the two and reserve the first term for patients younger than 16-18 (Peede and Epker, 1977; Petri, 1982; Geist et al., 1985). Rare as a primary tumour of bone (Freedman et al., 1978) it most frequently arises in the abdominal wall (Peede and Epker, 1977; Kraut, 1981) and the palmer and plantar fascia (Peede and Epker, 1977) and may be localized to one site or may be multifocal (Henefer et al., 1978). Al- though Peede and Epker (1977) claim that 40 % of the cases are reported in the head and neck, most authors con- sider it uncommon there or in the oral cavity (Melrose and Abrams, 1980; Kraut, 1981; Rodu et al., 1981; Petri, 1982) with only 28 cases reported (Freedman et al., 1978; Kraut, 1981; Geist et al., 1985). Twenty-five affected the mandible with 70 % involving the molar-angle-ramus area (Freedman et al., 1978; Geist et al., 1985) and only three

were found in the maxilla (Freedman et al., 1978; Kraut, 1981) There was an equal sex distribution (Peede and Ep- ker, 1977; Freedman et al., 1978) and the mean age was 15.7 (Freedman et al., 1978). Although fibromatosis may demonstrate rapid growth (Peede and Epker, 1977), it ap- pears more frequently as a painless, slow-growing, firm swelling with ill-defined borders that begins as a fibroblas- tic proliferation which gradually infiltrates and invades the surrounding soft tissues and bone (Peede and Epker, 1977; Freedman et al., 1978; Henefer et al., 1978; Mel- rose and Abrams, 1980; Kraut, 1981; Petri, 1982). Radiographically the lesion may appear as an unilocular or muhilocular radiolucency (Freedman et al., 1978; Geist et al., 1985) with borders that are usually well delineated (Freedman et al., 1978) and may demonstrate root resorp- tion. Histologically it is characterized by the abundance of well- differentiated spindle-shaped fibroblasts, which are sepa- rated by considerable collagen and/or reticular fibres. There is no prominent cellular pleomorphism and the fib- roblasts are rather uniform in size and staining characteris- tics and do not usually demonstrate mitotic activity, as the latter would imply fibrosarcoma rather than fibromatosis - an entirely different situation. The fibroblasts may be ei- ther small or plump, although occasionally both varieties may be found in the same lesion. The microscopic cellular- ity varies from tumour to tumour and from area to area in the same tumour and is most evident at the peripheral edge of the tumour thus explaining to a certain degree its behaviour. Some lesions are extremely cellular and must be differentiated from fibrosarcoma. The proportion of the collagenous component and the cellular fibroblastic com- ponent also varies. However, the hypercellularity of a fi- brous neoplasm in a child does not necessarily imply mal- ignant behaviour and even mitoses are not a consistent in- dex of malignancy when found in younger age groups (Shafer et al., 1974; Peede and Epker, 1977; Freedman et al., 1978; Henefer et al., 1978; Melrose and Abrams, 1980; Kraut, 1981; Rodu et al., 1981; Petri, 1982). The tumour is not encapsulated and the margins may be dis- tinct or diffuse. The histological pattern provides little or no information as to the potential of the tumour to grow or recur after surgery and must be differentiated from fib- rosarcoma as well as fibroma, giant cell tumour and fi- brous dysplasia. Although isolated cases have been treated with chemother- apy with encouraging results (Kraut, 1981), the treatment

Juvenile Fibromatosis J. Cranio-Max.-Fac. Surg. 16 (1988) 131

Fig. 1 Case 1. Right infraorbital swelling caused by fibromatosis. Fig.2 Case 1. A 2 x 2 mass with well defined borders removed from the infraorbital region.

Fig. 3 a Case 1. An area of the lesion showing highly cellular, in- Fig. 3 b Case 1. In the deeper layers the tumour mass change into terlacing bundles of fibroblasts (H&E x 60). regular bundles of fibrous connective tissue (H & E x 40).

13 2 J. Cranio-Max.-Fac. Surg. 16 (1988) N. Zachariades, S. Papanicolaou

Fig.4 Case 2. Mass involving the right anterior alveolus.

of choice remains surgical excision with a wide margin of normal tissue (Peede and Epker, 1977; Melrose and Abrams, 1980; Geist et al., 1985) avoiding procedures that would produce excessive mutilation (Henefer et al., 1978). Radiation therapy should not be administered be- cause of the potential hazards (Kraut, 1981). The tumour lies on the borderline between the benign and malignant (Rodu et al., 1981) and demonstrates multiple invading projections (Petri, 1982) that may reach 2-3 cm. beyond the palpable margins (Peede and Epker, 1977) al- though destruction of bone is not usually observed. The le- sion has a high recurrence rate, which has been estimated to be 50% (Peede and Epker, 1977) and over (Kraut, 1981), with most recurrences occurring during the first 1 -2 years (Henefer et al., 1978; Melrose and Abrams, 1980; Kraut, 1981). Although is does not metastasize (Sharer et al., 1974; Henefer et al., 1978), it may be fatal through local extension to vital structures (Peede and Ep- ker, 1977; Henefer et al., 1978).

Fig. 5 a Case 2. The lesion shows interlacing bundles of highly Fig. 5 b Case 2. At the periphery, the tumour is surrounded by cellular connective tissue (H & E x 45). fibro-fatty tissue (H & E x 45).

Juvenile Fibromatosis J. Cranio-Max.-Fac. Surg. 16 (I 988) 13 3

Fig.6 Case 3. Left submandibular swelling. Fig.7 Case 3. Radiograph of the left mandible showing some ra- diolucency of the mandibular body.

Case Reports

Case 1 A 5-year-old boy was seen because of a small swelling of the right infraorbital region (Fig. 1). There were no abnor- mal radiographic findings and the child was otherwise healthy. A hard mass was palpable both extraorally and intraorally. The child was admitted for further investiga- tion and exploration of the area. The laboratory findings were within normal limits. Under general anaesthesia the right infraorbital region was explored using an intraoral, trapezoid, mucobuccal flap. A 2 x 2 cm. mass (Fig. 2) with clearly defined borders was easily identified and removed without difficulty. There was no bone involvement. The histological diagnosis was fibromatosis (Fig. 3). The child did well postoperatively and during the 6 year post- operative period has shown no sign of recurrence.

Case 2 A &year-old boy was seen because of a mass involving the right anterior teeth, of one month's duration. The mass (Fig. 4) was hard in consistency, 3 cm. in its greatest diame- ter, had not displaced the teeth involved and was not asso- ciated with any specific radiographic findings. The remain- der of the clinical and laboratory findings were within normal limits. Under general anaesthesia, the mass, which demonstrated no clear borders, was removed with an ade- quate margin of what appeared to be normal tissue. The specimen was submitted for histological examination. It included the teeth and alveolar bone of the involved area. The diagnosis was fibromatosis (Fig, 5). There has been no sign of recurrence 5 years after the operation.

Case 3 A 3 ~-year-old girl was brought to the hospital because of a rapidly enlarging submandibular swelling which was first noticed a month previously and had been treated with antibiotics. The swelling was diffuse and firm in consisten-

cy (Fig. 6). Radiographically there was a radiolucency with no clear borders occupying the body of the mandible (Fig. 7). The remainder of the clinical and laboratory find- ings were within normal limits. Under general anaesthesia the submandibular area was ap- proached extraorally. A diffuse mass was discovered which occupied the submandibular triangle and was re- moved along with the submandibular gland. The mandibu- lar bone was also thoroughly curetted. The specimen was submitted for histological examination and was diagnosed as fibromatosis (Fig. 8). The patient did well postoperative- ly and was lost to follow-up until six months later when she was brought again with what appeared to be an obvi- ous recurrence. Readmission and treatment were suggest- ed, but the child was not seen again.

Discussion and Conclusions

It is now well established that aggressive fibromatosis in the soft tissues closely resembles desmoplastic fibroma of bone, where it is a rare primary tumour (Bertoni et al., 1986).The fibromatoses can be subdivided into two major groups, according to Allen (1977) and Enzinger (1983): superficial and deep. In the former group (also described as fascial) are the palmar and plantar varieties, penile fibromatosis and the knuckle pads. In the latter (musculo- aponeurotic) group, extra-abdominal, abdominal and in- tra-abdominal fibromatoses are included (as are intra-ab- dominal pelvic fibromatosis, mesenteric fibromatosis and Gardner's Syndrome). The superficial type is slow growing and of small size, rarely involving deeper structures. As the spectrum of clinical behaviour and histological pat- terns vary considerably in fibromatosis it is often difficult to make the correct diagnosis until the passage of many years after the first biopsy, until the outcome seems cer- tain (Melrose and Abrams, 1980). The diagnosis may be particularly difficult in children (Melrose and Abrams,

13 4 ]. Cranio-Max.-Fac. Surg. 16 (1988) N. Zachariades, S. Papanicolaou

Fig. 8 a Case 3. Highly cellular areas of the tumour featuring large fibroblasts with spindle-shaped nuclei (H & E x 150).

Fig. 8 b Case 3. Superficially the lesion extends diffusely towards the overlying epithelium (H & E x 75),

1980) since some fibrous tumours are very cellular and grow rather rapidly in this age group. Tumours of fibrous connective tissue are not usually contained in a well de- fined capsule and the clinical and histological borders do not necessarily coincide. In addition, the aggressiveness (Henefer et al., 1978) of such neoplasms cannot always be determined on histological grounds, and criteria such as cellularity and/or pleomorphism may not be good predic- tors. Aggressive fibromatosis, an appropriate term in our opinion, may be the missing link between benign and mal- ignant lesions of fibrous connective tissue origin. These le- sions show varying degrees of potential for local infiltra- tion, although the histological and clinical criteria for clas- sification as sarcoma may be absent. Although the lesion may cause death by local invasion, it does not metastasize. It appears that involvement of bone, as shown in our third case, is characteristic of a more advanced and/or aggressive lesion, capable of penetrating hard tissues. The rapid growth in that particular case is another factor indicating the aggressive behaviour of the neoplasm. The recurrence, however, can also be attributed to the lack of welt-defined

borders that may have resulted in inadequate removal of the lesion and the fact that the bone was simply curetted instead of being subjected to a more radical (and mutilat- ing) procedure. We chose the term juvenile instead of aggressive, because we consider it safer to characterize the lesion in relation to the age group affected rather than its behaviour, the latter being unpredictable. It appears that the first operation provides the best chance of cure.

References

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