Malignant Fibrous Histiocytoma Of The Anterior Maxilla

Abstract

Malignant fibrous histiocytoma (MFH) is the most common soft-tissue sarcoma, but is relatively uncommon in head and neck area. Histologically, it is difficult to distinguish this tumor from other sarcomas and carcinomas. Surgery is the most reliable treatment for MFH, but the 5-year survival rate for cases of this tumor in the head and neck is low in comparison with MFH of the extremities and trunk. Around 61 cases reported in the international literature since 1974. We present a rare case of primary MFH of the maxilla in the unusual location of maxilla in a 20-year-old female. The tumor was located in the maxillary anterior region mimicking periodontal ulcer. We have described the difficulty in diagnosing the tumor along with differential diagnosis, histopathological diagnosis, and current methods in diagnosing the tumor i.e. immunohistochemical analysis. The literature was reviewed briefly along with treatment guidelines.

Histiocytoma, Dental, Maxilla

Introduction
Tumors which are composed of cells differentiating as both fibroblasts and histiocytes have been designated fibrous histiocytomas, although only a small percentage of these lesions behave in a malignant fashion; they are called malignant fibrous histiocytoma, MFH.(2),(4) MFH arises predominantly in soft tissue, especially in the trunk and extremities,(5) and is one of the most common malignant tumors among the elderly, with a peak incidence in the fifth through the seventh decades of life.(6)

The term was introduced in 1963, (1) as it was believed that the tumor arose from histiocytes acting as facultative fibroblasts. Although current thinking is that the term histogenesis is related to fibroblasts themselves, the term, malignant fibrous histiocytoma has been retained for convenience, as it is descriptive of a clinico-pathological entity. The etiology of MFH is unknown. However, in long bones, there is a strong association between medullary bone infarcts and the subsequent development of osteosarcoma and malignant fibrous histiocytoma.

Malignant fibrous histiocytomas can arise from soft tissue or bone. Their occurrence is most common in the soft tissues of the abdomen and extremities, while 23% of histiocytomas occur at osseous sites. Although they can be found in the head and neck region, their occurrence is uncommon, accounting for 3–8.5% of the cases.(6),(7) The peak occurrence is in persons aged 50–70 years. A slight male predominance is observed. They can occur everywhere, owing to their mesenchymal origin.(2),(3) The most common sites of occurrence in the head and neck, are the sino-nasal tract,(8)soft tissues of the neck, craniofacial bones, and salivary glands. A literature search showed around 61 well-documented cases of malignant fibrous histiocytoma arising at the maxilla, maxillary sinuses and zygoma.(11)-(40)

We describe an interesting case of unusual location of tumors that had been diagnosed at a late stage, in the maxilla (anterior). The present case demonstrates the typical difficulty in recognizing this tumor.

Case Report

A 20 year old female came to the Department of Oral Medicine with a complaint of a 4 month old ulcer in the upper jaw, in the front region of the gums. The patient gave a history of tooth brush trauma in the maxillary anterior gingival area, followed by an ulcer which persisted for 4 months. There was no history of vesicle or bullae prior to the ulcer formation. A provisional diagnosis of pyogenic granuloma/chronic fungal infection was given, and the patient was referred to the Department of Periodontics.

A course of antibiotics were given to the patient, and an incisional biopsy was taken, which was not conclusive. A repeat biopsy of the lesion was taken, histopathological and special stain (Reticulin positive) studies were done, which gave the diagnosis of Malignant Fibrous Histiocytoma (Storiform Type), and the patient was referred to the Dept. of Oral Surgery for further management.

On examination of the lesion –it was observed that the gingiva was red in color and inflamed with respect to the upper central incisors, with ulceration measuring 2cm in size and extending upto the middle third of the upper central incisors and the mucogingival junction (Table/Fig 1). The lesion was severely tender on palpation, with bleeding on probing, and grade III mobility of the upper central incisors. No cervical lymph nodes were palpable. Chest radiographs and biochemical and hematological investigations showed no evidence of metastases. Axial and Coronal CT scan of the facial bones demonstrated a minimally enhancing soft tissue density mass lesion, measuring about 3x1.5 cm, seen in the midline in the superior gingivolabial sulcus. The underlying bone of the alveolar process of the maxilla showed scalloping without frank destruction (Table/Fig 2). A Bone scan revealed no abnormal skeleton uptake.

At operation under general anaesthesia, resection of the premaxilla was done, with extraction of the upper anterior canine and excision of the labial and palatal mucosa with 1.5 cm clearance margins. The BIPP pack was given into the defect, and was covered by a surgical obturator.

Histological examination of the surgical specimen showed a tumor composed of numerous fibroblasts, macrophages, and atypical cells, with evidence of numerous mitotic figures admixed with numerous proliferating blood vessels, with a lumen filled with RBC’s. The macrophages were arranged in a storiform pattern. Certain areas showed a myxomatous degeneration (Table/Fig 3).

The surgical margins were free of tumor. The diagnosis of Malignant Fibrous Histiocytoma was confirmed after routine histology and special stains like reticulin.

Postoperatively, patient recovery was uneventful. In the patient follow up, during the course of 4 months, healing was adequate, with no complaints. An interim obturator was given. The patient was explained about the postoperative chemotherapy, for which she was not willing. The patient remains free of disease, with minimal aesthetic deformity, and is tolerating her prosthesis well, 6 months postoperatively (Table/Fig 4)

Discussion

Stout(2) coined the term malignant fibrous histiocytoma on the basis of tissue culture studies made by Margaret Murray, which purportedly showed that these pleomorphic fibroblastic tumors arose from tissue histiocytes capable of fibroblastic transformation which are called ‘‘facultative fibroblasts’’. Enzinger and Weiss subsequently defined five subtypes of MFH as follows: (1) Storiform-pleomorphic, (2) myxoid, (3) giant cell, (4) inflammatory, and (5) angiomatoid. MFH is the most common adult soft tissue sarcoma.(9)

Recently, there are controversial entities regarding tumors of fibroblastic differentiation. The ubiquitous fibroblast is capable of a wide variety of morphological and functional adaptations with respect to its body site, as well as local physiological and pathological changes. The active collagen synthesizing fibroblast is a spindle shaped or plump epithelioid cell with prominent juxtanuclear Golgi apparatus, and well developed branching rough endoplasmic reticulum (RER).(10) There is a longstanding disagreement as to whether the cell type composing MFH is a histiocyte or a fibroblast. Initially, it was proposed by Ozzello et al.(1) that the cell was ‘‘facultative fibroblast’’ (a histiocyte that could appear and function as a fibroblast). However, the majority of more recent histochemical, immunohistochemical, and ultrastructural studies of this tumor support the contention that MFH is a form of fibrosarcoma.(9),(10) Previously, the diagnosis was made on the basis of the histological appearance. Recently, distinction among these pleomorphic soft tissue tumors is best achieved by a joint immunohistochemical and ultra structural study.(10)

Malignant Fibrous Histiocytoma is the most common soft tissue sarcoma, first described by Ozzelo et al. and O’Brien and Stout(1),(2) The storiform-pleomorphic type is the most common, and is a highly cellular tumor, which can range from well differentiated to anaplastic. MFH affects individuals later in life, and occurs more often in men, with an approximate 2:1 male: female ratio.

Maxillary MFH is very rare. It was first reported in 1974.(40) The review of the literature produced 61 well-documented cases of maxillary malignant fibrous histiocytoma(11)-(40) ranging in age from 12 to 83 years, with a median age of 44.7 years. Most patients 54/61 (88.5%) showed clinical signs of primary maxillary MFH. MFH can also arise in the site of previous radiation. However, radiation induced MFH of the head and neck is exceedingly rare. A literature search showed only 7/61 cases (11.47%) of post-radiation maxilla MFH.(19)(20)(26)(33)(35) The sinonasal tract has been reported to be the commonest site (30%) of tumor involvement in the head and neck region(8) But Sabesan et al.(12) found that maxilla is the most common site (15/54 cases). This literature review of Maxilla MFH revealed that 41/61 cases (67.2%) of the lesions occurred in the maxilla(11)-(15),(17),(18),(20)-(30),(32)-(40) while only 5/61 cases (8.19%) occurred in the maxillary sinus,(14),(19),(30), and only two cases (3.2%) were reported to have occurred in the post-maxillary and alveolar ridge

Conclusion

Malignant Fibrous Histiocytoma is an aggressive tumor with potential for both local recurrence and hematogenous metastatic spread. Clinicians should not overlook any kind of gingival ulcer or swelling that may not appear distinct visually, and therefore consider it to be a part of the normal anatomy, an anomaly with no significance, or treat them injudiciously. An accurate diagnosis should be established prior to any surgical treatment using histological analysis and special stains. MFH should be treated aggressively with the main modality of treatment as surgery, followed by combined radiotherapy and chemotherapy.