Cystic, melanotic ameloblastic fibroma with granulomatous inflammation

Short communications & case reports

Cystic, melanotic ameloblastic fibroma with granulomatous inflammation M. B. Edwards, B.D.S., F.D.S.R.C.S. (Eng.),* and G. F. Goubran, B.D.S., M.B., B.S., L.R.C.P., M.R.C.S., F.D.S.R.C.S. London and East Grinstead, England DEPARTMENT

OF DENTAL

DEPARTMENT

OF ORAL

(Eng.),**

SCIENCE, ROYAL COLLEGE OF SURGEONS OF ENGLAND, AND SURGERY,

QUEEN

VICTORIA

HOSPITAL,

EAST

GRINSTEAD

A large mandibular tumor which had the cellular features of ameloblastic fibroma but was cystic and complicated by granulomatous inflammation is described. The epithelial component contained melanin. The pathogenesis of the cystic change is discussed, and the lesion is compared to the proposed papilliferous variant of this odontogenic neoplasm.

typical ameloblastic fibroma of the jaws is a Tsolidhetumor. A single casehasbeendescribed’ in which there was a substantial cystic lumen lined with a papillary proliferation of epithelium. This was regardedas a morphologic variant of the neoplasm termed “papilliferous ameloblastic libroma. ” The present article describes another cystic ameloblastic fibroma that shared features in common with the papilliferous variant and contained intraepithelial melanin. CASE REPORT

An 18-year-old black African man came to the Maxillofacial Unit of the ABU Hospital in Kaduna, Nigeria, for treatment of a large swelling on the right side of the head, caused by a blow from a blunt instrument on the previous day. There was a massivesubcutaneoushematomaat the site of injury, as well as facial asymmetry on the opposite (left) side due to enlargementof the body of the mandible. The buccal plate of the left mandible was grossly expanded,the deciduouscuspid and molars had been retained, and the permanentcuspid was displaced buccally. None of these teeth was carious. Extraoral radiographs(Fig. 1) showed a unilocular radiolucency with a corticated margin occupying the entire mandible from *Research Fellow in Oral Pathology. to the Maxil**Senior Registrar in Oral Surgery; formerly seconded lofacial Unit, ABU Hospital, Kaduna, Nigeria. 0030-4220/80/040333+~00.40/0

0

1980 The C. V. Mosby Co.

Fig. 1. Lateral oblique radiograph showing large radiolucent lesion of the mandible with a corticated margin.

the right cuspid to the permanent molar on the left and encroaching upon the ascending ramus. The roots of the retamed deciduous teeth were resorbed. Those of the solitary

permanent molar were incomplete in the apicalquarter,but the periapical lamina dura was preserved and there was no evidence of resorption. This tooth was regarded as either a second molar or a third molar in an advanced state of development. No account was given of the loss of the first molar. 333

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Fig. 2. Photomicrograph of cystic ameloblastic fibroma showing numerous nests and strands of odontogenic epithelium in the cyst wall and a dark band of granulomatous inflammation at the luminal surface. (Hematoxylin and eosin stain. Original magnification, ~2.5.)

Fig. 3. Detail of nests, strands, and microfollicles of odontogenic mesenchyme. (Hematoxylin and eosin stain. Original magnification, x 187.)

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The hematomaof the scalp was treated, and an incisional biopsy of material from the mandibular tumor demonstrated the microscopic features of ameloblastic fibroma. One week later, with the patient under endotracheal anesthesia,the lesion was easily enucleated and found to be cystic. One year later there had been no recurrence. Pathologic eummination

The fixed surgical specimen was an opened, thick-walled cyst with over-all dimensions of 50 by 36 by 15 mm. The outer surface was smooth as if encapsulated.Thin, parallel slices through the cyst showed variation from some 3 to 10 mm. in the thickness of the wall and uniformly pale, featureless cut surfaces. Sections showed the cyst wall to be composed of cellular mesenchymesimilar in appearanceto the primitive dental papilla. This enclosedinnumerable nestsand strands of odontogenic epithelium (Fig. 2), some of which formed microfollicles with a columnar basal layer exhibiting reversed nuclear polarity (Fig. 3). Many epithelial islands contained a brown pigment which could be removed by prebleaching and was stained by the Masson-Fontana and Schmorl techniques for melanin. The luminal surface was nodular or papillary and lined with epitbelium which was variously either squamousin type or more obviously odontogenic (Fig. 4). Focally, this formed a plexiform atrangement that connected with the epithelial islands embeddedin the cyst wall. Beneath the lining was a broad band of granulomatous inflammation (Fig. 5), rich in plasma cells, that enclosed clusters of giant mononuclear cells 50 to 80 rnp in diameter. These cells had a clear or faintly granular, vacuolated cytoplasm and pyknotic nuclei, sometimesdisplaced to the cell membrane. A variety of special stains was applied; PAS, Giemsa, Gram, Zeihl-Neelsen, Warthin-Faulkner silver impregnation, and auramine-rhodamine fluorochrome for lepra bacilli failed to reveal microorganisms. The oil red 0 method on frozen sectionsdid not show lipid within the large vacuolatedcells. Perls’ Prussianblue reaction demonstrateda patchy distribution of hemosiderin within the granulomatous zone. DISCUSSION The age of the patient, the site and radiographic appearance of the tumor, and its essential microscopic features may all be regarded as typical for ameloblastic fibroma.2 Two premolars and possibly the first permanent molar were congenitally absent at the site of the lesion. The previously described’ cystic ’ ‘papilliferous ameloblastic fibroma” was at the same site and similarly encapsulated by fibrous tissue and sclerotic bone. It was also associated with a dental anomaly described as a supplemental premolar. In contrast to the papilliferous variant, the tumor described here lacked the substantial papillary cords of odontogenic epithelium which had produced fingerlike projections at the luminal surface. Instead, the surface was nodular and lined with a flatter, squamoid epithelium associated with an established chronic inflammatory infiltration. Con-

Fig. 4. Detail of thinner part of the cyst wall showing lining of squamoid epithelium, subepithelial chronic inflammation with large, clear cells, epithelial and mesenchymalelements of ameloblastic fibroma, and a peripheral band of fibrous tissue. (Hematoxylin and eosin stain. Original magnification, X77).

tinuity of this lining epithelium with a plexiform proliferation of odontogenic epithelium within the granulomatous band left little doubt that it originated from the epithelial component of the tumor rather than from a contribution of oral epithelium. The giant vacuolated mononuclear cells within the inflammatory infiltrate were regarded as effete histiocytes. Small cysts are occasionally noted” within ameloblastic fibromas, but these are not usually epithelized. Microcystic degeneration can occur within larger follicles of the neoplastic epithelium, but it is not likely that enlargement of a cystic follicle accounted for the macrocystic structure of this tumor. Since the mesenchymal component of the neoplasm is delicate and contains sinusoidal vascular spaces, we suggest that damage, degeneration, or hemorrhage in this tissue can lead to cavitation which is secondarily epithelized by proliferating neoplastic epithelium. Such a proliferation was an obvious feature of the “papilliferous ameloblastic fibroma”’ When accompanied by chronic inflammation, metaplastic change to the flatter and more squamoid integument found in the present lesion

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Fig. 5. Plexiform proliferation of epithelium from the cyst lining in continuity with the epithelial component of the neoplasm. Numerous clear cells are present in the surrounding inflamed mesenchyme. (Hematoxylin and eosin stain. Original magnification, X 100.)

could occur. Neither infection nor direct communication with the oral cavity could be,demonstratedto account for the inflammation, which may therefore have been attracted by the accumulation of chemotactic metabolites within the developing cyst. The potential for such changesto occur may be present in any large and long-standing ameloblastic fibroma. Melanin has been described within the epithelial cells of a number of odontogenic tumors or malformations. These include the calcifying odontogenic cyst,4 an “ameloblastic odontoma”5 which contained “ghost cell ” keratinization in cystic and follicular odontogenic epithelium similar to the calcifying odontogenic cyst, a solid tumor,6 photomicrographsof which suggesta variant of calcifying epithelial odontogenic tumor, and ameloblastic fibro-odontoma.’ The latter is closely allied to the ameloblastic fibroma in which available accounts suggest that melanin is rarely found. The pigment is presumably donated by dendritic melanocytes, although these could not be clearly identified in our case. Such cells, however, do occur in the dental lamina and tooth buds,* and there is no reason why they should not be incorporated into odontogenic tumors. We are grateful to Dr. E. 0. Adekeye for permission to

publish this case under his care and to Professor B. Cohen for his criticism of the manuscript. REFERENCES 1. Christ, T. F., Cavalaris, C. J., and Cracker, D. J.: Papilliferous Ameloblastic Fibroma, ORALSURG.34: 806810, 1972. 2. Trodahl, J. N.: Ameloblastic Fibroma, ORAL SURG. 33: 547-558, 1972. 3. Grenfell, J. W., and Maris, A. M.: Ameloblastic Fibroma, ORAL SURG. 21: 403406, 1966. 4. Gorlin, R. J., Pindborg, J. J., Redman,R. S., Williamson, J. J., and Hansen, L. S.: The Calcifying GdontogenicCyst, Cancer 17: 723-729, 1964. 5. Duckworth, R., and Seward, G. R.: A Melanotic Ameloblastic Gdontoma, ORAL SURG. 19: 73-85, 1965. 6. Richardson, J. F., Balogh, K., Merk, F., and Booth, D.: Pigmented GdontogenicTumor of Jawbone, Cancer34: 1244-1251, 1974. 7. Eda, S., Tokuue, S., Kato, K., Uchida, E.. Yoshida, T., Hayasbi, T., and Kawakaml, T.: A Melanotic Ameloblastic Fibro-odontoma, Bull. Tokyo Dent. Coll. 18: 119-128, 1977. 8. Lawson, W., Abaci, 1. F., and Zak, F. G.: Studies on Melanocytes, ORAL SURG. 42: 375-380, 1976. Reprint

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Mr. M. B. Edwards Department of Dental Science Royal College of Surgeonsof England 35-43 Lincoln’s Inn Fields London WCZA 3PN, England