Pediatric Surgical Management of Cystic Ameloblastic Fibroma—Mural Type: A Rare Enigmatic Pathology

ABSTRACT

Introduction

Cystic ameloblastic fibroma (CAF) is an uncommon mixed odontogenic tumor. It is rare in children and has a mean age of 15.9 years, commonly seen in the posterior mandibular region. The mural type of CAF is an even rarer subtype, characterized by the presence of cystic spaces lined by tumor cells.

Aim

To document the clinical, radiographic, histopathological features, and surgical management of a rare case of cystic ameloblastic fibroma–mural type in an 8-year-old male. The report also aims to provide insights into the diagnosis and treatment of this rare odontogenic tumor in the pediatric population.

Case description

We present a case of an 8-year-old male who was diagnosed with a mural type of CAF. The patient presented with facial asymmetry and painless swelling of the right mandible. Diagnosis was confirmed through clinical, radiographic, and histopathological examinations, following which a management plan involving the extraction of affected teeth and the surgical excision of the lesion was performed. A 2-year follow-up showed no recurrence.

Conclusion

This report highlights the importance of early diagnosis and prompt management of CAF during the mixed dentition stage. Small lesions may be treated conservatively, but extensive lesions require radical treatment. This case is the first documented instance of CAF in the Asian population and the second occurrence in patients under 10 years old. It outlines the management protocol for CAF in younger patients with mixed dentition, emphasizing the importance of early intervention for positive outcomes.

How to cite this article

Gaviappa D, K VK, Augustine D, et al. Pediatric Surgical Management of Cystic Ameloblastic Fibroma—Mural Type: A Rare Enigmatic Pathology. Int J Clin Pediatr Dent 2025;18(7):871–878.

KEY MESSAGES

This case of CAF is the first report in the Asian population and the second occurrence in patients under 10 years old. It outlines the management protocol for CAF in younger patients with mixed dentition, emphasizing the importance of early intervention for positive outcomes.

INTRODUCTION

Ameloblastic fibroma (AF) is a rare type of mixed odontogenic tumor that typically occurs from childhood through young adulthood, with an average age of 15.9 years and a median age of 13 years at diagnosis.¹ It most often affects the posterior region of the mandible. According to the World Health Organization (WHO), AF is characterized by odontogenic ectomesenchymal tissue resembling dental papilla, along with epithelial strands and nests similar to the dental lamina and enamel organ.² AF is considered a true mixed tumor because both its epithelial and ectomesenchymal components are neoplastic, although no dental hard tissues are formed. Two uncommon variants of AF exist: the granular cell type and the peripheral type. There is an ongoing debate in the literature regarding whether management should be conservative or aggressive in its approach. Generally, conservative approaches such as enucleation and curettage are effective, but larger, more extensive lesions may require more radical surgical intervention.³

Cystic ameloblastic fibroma (CAF) can originate from the wall of a dentigerous cyst. In such instances, there is an observed presence of a lining consisting of cystic tissue, along with connective tissue areas resembling AF. In true cases of CAF, it is essential for the cystic lining to closely resemble the epithelial component of AF and exhibit a direct connection to characteristic AF regions at the cyst wall.^4,5 Based on these distinctive features, the presented case strongly aligns with the diagnosis of CAF.

In this case report, we present an unusual manifestation of ameloblastic fibroma referred to as a mural cystic variant, characterized by the presence of conventional ameloblastic fibroma within the cyst wall. Only five cases of CAF have been reported in the literature; this is the first case reported in the Asian population and only the second case reported in the under-10-year age group. The demographic features of the earlier reported five cases are shown in Table 1. The present report also delineates the management protocol in the younger age group with mixed dentition for CAF that has not been described in the earlier cases reported.

Table 1:

Demographic features reported till date in the literature as cystic ameloblastic fibroma

S. No.	Author	Year	Sex	Age	Site	Ethnicity
1	Christ et al.6	1972	Female	15	Mandible	Black
2	Edwards and Goubran7	1980	Male	18	Mandible	Black
3	Economopoulou and Sotiriadou8	1998	Female	26	Mandible	White
4	Usubütün et al.9	2002	Male	17	Mandible	Middle Eastern
5	Ali et al.10	2020	Male	08	Maxilla	White
6	Current Case	2022	Male	08	Mandible	Asian

Early diagnosis of such lesions is important in the pediatric population because of rapid odontogenic development in the jaw areas.¹¹ One aspect of concern in cases of ameloblastic fibroma (AF) affecting young individuals is the possibility of the condition transforming into a malignant form known as ameloblastic fibrosarcoma. It is worth noting that approximately 25% of fibrosarcomas develop from recurrent AF cases.¹² The aim of the present article is to report this unusual variant and highlight its surgical and prosthetic management in the pediatric population. The manuscript also emphasizes the differential diagnosis of rare odontogenic lesions.

CASE DESCRIPTION

Presentation

An 8-year-old male reported to the Department of Pediatric and Preventive Dentistry with a chief complaint of swelling in the lower right posterior tooth region for 10 days. On examination, the patient had swelling approximately 3 × 3 cm in size, obliterating the right lower vestibule and extending from teeth 83, 84, and 85. An orthopantomogram revealed a well-defined unilocular radiolucency in the right body of the mandible with a corticated border. Superoinferiorly, it extended from the cervical third of 84 and 85 to the lower border of the mandible. Mediolaterally, it extended from the distal root of 82 and 83 to the mesial root of 46 (Fig. 1).

Fig. 1:

Orthopantomogram reveals a well-defined unilocular radiolucency in the right body of the mandible with a corticated border

Histopathology, Special Staining, and Diagnosis

Under aseptic conditions, extraction of 84 and 85 was done, and an elliptical incision was given over the swelling present in the right mandibular body region under local anesthesia. The overlying mucosa and cystic lining were excised and sent for histopathologic examination. Microscopic analysis showed lining epithelium, cystic lumen, and an inflamed connective tissue capsule. The lining epithelium was thin and stratified squamous in many areas with an arcading pattern (Figs 2A and B). The connective tissue appeared immature and myxoid with numerous plump spindle- and stellate-shaped cells. Odontogenic cells were observed in the connective tissue stroma in the form of oval to round islands and long strands of varying length (Figs 2C and D). Numerous blood vessels were seen with prominent zones of hyalinization. Van Gieson special stain was used to detect ghost cells and dentinoid to rule out calcifying odontogenic cyst (Fig. 3). Alcian blue and crystal violet were employed to demonstrate the myxoid connective tissue and densely collagenized areas (Fig. 4). A final diagnosis of cystic ameloblastic fibroma was established.

Figs 2A to D:

(A) Lining epithelium, stratified squamous in many areas with an arcading pattern; (B) Immature and myxoid connective tissue with numerous plump spindle- and stellate-shaped cells; (C) Odontogenic cells in the form of oval to round islands and long strands of varying length; (D) Circular odontogenic islands with prominent nuclei

Figs 3A to D:

Van Gieson special stain used to detect ghost cells and dentinoid to rule out calcifying odontogenic cyst. (A to D) No yellow-staining ghost cells or pink-staining dentinoid were detected

Figs 4A to D:

Alcian blue and crystal violet demonstrating the myxoid connective and densely collagenized areas

Management

Extraction of 84 and 85 was done under local anesthesia. A full-thickness elliptical mucosal incision was given over the swelling present in the right mandibular body region (Fig. 5A). The cystic lining was exposed after the initial mucosal incision. Partial excision of the cystic lining was done, taking care not to damage the underlying permanent tooth buds. The cystic content was cleared and irrigated thoroughly with saline. The excised lining was sent for histopathological examination and the cystic cavity was packed with ribbon gauze (Fig. 5B). The patient was recalled for dressing changes every alternate day, and an obturator/space-occupying cold cure acrylic stent was fabricated after making an impression of the defect opening and surrounding area using condensation silicone impression material after the initial inflammatory response (Fig. 5C).

Figs 5A to D:

(A) Full-thickness elliptical mucosal incision; (B) Cystic cavity packed with ribbon gauze; (C) Obturator/space-occupying cold-cure acrylic stent fabricated; (D) Second-stage surgical procedure for complete enucleation of the remaining cystic lining

Follow-up was done every 15 days until the decompressed cavity had shrunk to a significantly smaller size and adequate bone formation had occurred around the teeth and within the cavity. Later, after the eruption of the permanent teeth, the patient was recalled for the second-stage surgical procedure, which comprised complete enucleation of the remaining cystic lining. The wound was closed primarily (Fig. 5D).

Follow-up

No recurrence has been noted after a 2-year follow-up at the time of reporting this case. Normal bone formation was observed during the post-treatment examination (Fig. 6).

Figs 6A to C:

(A) Adequate spacing maintained after a 2-year follow-up; (B) Satisfactory occlusion achieved; (C) OPG showing normal bone formation and erupting permanent teeth

DISCUSSION

The terminology “cystic ameloblastic fibroma” was first employed by Meyers et al. in 1991.⁴ Usubütün et al. also utilized this term in 2002 to characterize a pseudocyst displaying odontogenic epithelium resembling ameloblastic fibroma.⁹ Nevertheless, a comprehensive delineation of these neoplasms presenting ameloblastic fibroma tissue and cystic cavities is currently lacking in the literature.

Ameloblastic fibroma is considered a true mixed odontogenic tumor. Among the mixed odontogenic tumors, it is the least differentiated, as its neoplastic components typically do not produce dentin or enamel matrix—features that are characteristic of more differentiated tumors.¹³

It generally does not undergo cystic transformation except in rare cases; in such instances, it is referred to as CAF. The current case has been discussed under the following headings: pathologic mechanism, diagnostic criteria, differential diagnosis, management, and prognosis.

The scarcity of the present case report holds significant clinical importance, as it highlights the dearth of information available regarding CAF in the Asian population, particularly in the younger age group. The paucity of cases reported in individuals under 10 years of age underscores the novelty of this case and emphasizes the need for further research in this area. Furthermore, the report delineates a comprehensive and interdisciplinary management protocol for CAF in the mixed dentition stage, which is an essential period of dental development and has received relatively inadequate consideration in existing literature. The detailed management approach outlined in the report provides a valuable reference for clinicians managing comparable cases in the future. In summary, the rarity of the case and the extensive management protocol make this report a significant contribution to the existing literature on CAF.

Pathologic Mechanism of Development

We suggest three potential pathways that could account for the cystic variations seen in CAF. Both inflammatory lesions (such as radicular cysts) and malignant odontogenic lesions (such as ameloblastomas and unicystic ameloblastomas) are known to exhibit cystic degeneration of the odontogenic epithelium.⁸ Alternatively, when the odontogenic epithelium is injured due to surgical intervention or biopsy in the affected area, it can undergo reorganization, leading to the formation of a cavity that may expand either through hydrostatic pressure or due to neoplastic proliferation of the lining.¹⁰ In our specific case, it is plausible that all three of these mechanisms contributed to the development of the cyst. The inflammatory response and direct trauma from the surgery likely triggered epithelial cell proliferation and cyst enlargement. This highlights the inherent capacity of epithelial cells in CAF to expand and suggests a possible interplay between inflammation, trauma, and neoplastic processes in cyst formation.

Diagnostic Criteria for Cystic Ameloblastic Fibroma

Based on the available literature on CAF, we can outline its diagnostic features as follows. CAF is typically seen in young patients within their first to third decades of life, with a mean age of onset of 14.6 years and an age range of 7 to 26 years, with no apparent gender predilection.¹⁰ However, the present case report describes a rare occurrence of CAF in an 8-year-old male patient. This finding is consistent with the limited incidence of this odontogenic tumor in young children, as documented in the current literature.

Radiographically, CAF is characterized by the presence of a unilocular radiolucent area, typically seen in association with an unerupted tooth. The mandible is the predominant site of involvement in most cases.^14,15

The current case also exhibited a unilocular radiolucency with a corticated border extending from the cervical third of 84 and 85 to the lower border of the mandible and from the distal root of 82 and 83 to the mesial root of 46, resembling a dentigerous cyst radiographically. Notably, no radiopaque mass was present within the lesion.

The provisional diagnosis of CAF in the current case is consistent with the existing literature, which suggests that CAF commonly manifests as a dentigerous cyst accompanied by ameloblastic fibroma-like regions in the surrounding vicinity.

Microscopic features and subtypes: CAFs are characterized by the presence of classic AF areas in a cystic lesion. These AF regions consist of interconnected odontogenic epithelial strands and islands within a myxoid stroma containing abundant stellate-shaped fibroblasts resembling dental papilla. The epithelial components comprise spindle-shaped cells resembling stellate reticulum and columnar ameloblast-like cells located at the periphery. Cystic ameloblastic fibroma can be classified into two subtypes: intraluminal cystic ameloblastic fibroma (ICAF) and mural cystic ameloblastic fibroma (MCAF).^10,16

In cases of ICAF, the AF components are confined to the cyst's lining and do not extend into the surrounding wall, while MCAF is identified by the presence of AF components in both the cyst lining and the cyst wall.

The histological examination of the present case revealed the characteristic features of CAF. The lesion exhibited a cystic structure with dispersed interconnected odontogenic epithelial strands and islands within a cell-dense stroma that had a myxoid appearance. The immature, myxoid connective tissue capsule contained odontogenic cells that exhibited a spindle- and stellate-shaped morphology. The lining epithelium was thin, stratified squamous, and displayed an arcading pattern in some areas. Overall, these features align with the expected histological characteristics of CAF.

The case is distinguished from a dentigerous cyst with hyperplastic odontogenic epithelium by the presence of typical ameloblastic changes in the lining and periphery of the cyst, as well as the presence of a characteristic AF neoplastic stroma. The summary of clinical, radiographic, and histopathologic features of CAF is displayed in Table 2.

Table 2:

Clinical, radiographic and histopathologic features reported till date in literature as cystic ameloblastic fibroma

S. No.	Author	Presenting symptom and history	Radiographic features	Histopath subtype	Other features	Management
1	Christ et al.6	The patient complained of intermittent swelling and pain for 4–5 weeks	Expansion of the labial plate of bone, and radiographs revealed a 4.0 by 3.5 cm. Radiolucency between the lower left premolars was noted	Intraluminal (Papilliferous ameloblastic fibroma was suggested)	Within the immature connective tissue were cords and nests of odontogenic epithelium. In the central area of the mass, the odontogenic epithelium was markedly proliferative and papillary, with the formation of a cystic lumen	Enucleation
2	Edwards and Goubran7	Trauma to the scalp. Facial asymmetry on the opposite (left) side due to enlargement of the body of the mandible.	The buccal plate of the left mandible was grossly expanded, and the deciduous cuspid and molars had been retained. Unilocular radiolucency with a corticated margin	Mural	Numerous nests and strands of odontogenic epithelium in the cyst wall and a dark band of granulomatous inflammation at the luminal surface. 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	Under endotracheal anesthesia, the lesion was easily enucleated and found to be cystic
3	Economopoulou and Sotiriadou8	Pain in the left mandible Facial swelling had developed 1 year after blunt trauma	Radiolucency associated with the apical region of the lower left second premolar and first and second molars, with mobility	Mural	Cords and islands of odontogenic epithelium are associated with a cellular stroma in the cyst capsule	Under local anesthesia, the entire lesion was enucleated, with marginal resection of healthy bone and extraction of the involved teeth
4	Usubütün et al.9	No symptoms present, the lesion was found incidentally in a routine radiological examination. No history of trauma	Radiological examination showed a unilocular cyst with well-circumscribed borders associated with an unerupted third molar between the second molar and the ascending ramus	Mural	The cyst had no epithelial lining. The epithelial component showed two different patterns, the dominant one of which was narrow cords or small islands of odontogenic epithelium. The other pattern included epithelial cells forming small islands that resembled the follicular stage of the developing enamel organ, and showed peripheral columnar cells surrounding a mass of loosely arranged epithelial cells that resembled stellate reticulum	The cyst was enucleated, and the associated unerupted tooth was extracted
5	Ali et al.10	Unerupted tooth	Unerupted tooth 16, multiple small flecks of radiopaque material pericoronal to 16 and distal to tooth 55	Mural	Cyst lining revealed a palisading odontogenic epithelial component seen in the cyst. Epithelial islands were connected and seen directly originating from the basal aspect of the cyst lining	Tooth 16 was surgically exposed, and an excisional biopsy was performed
6	Current Case	Swelling in the lower right back tooth region for 10 days	Well-defined unilocular radiolucency seen in the right body of the mandible with a corticated border	Mural	Thin lining epithelium with an arcading pattern. Immature and myxoid stroma with plump spindle and stellate-shaped cells. Odontogenic cells are observed as oval to round islands and long strands of varying lengths	Extraction of 84 and 85 was done. The cystic content was evacuated, and the premolars 44 and 45 were exposed. An obturator/ acrylic stent was placed by the end of the 3rd or 4th dressing

Differential Diagnosis

The newly identified primordial odontogenic tumor (POT) shares significant histological similarities with CAF. Although the mesenchymal component of POT may exhibit a cell-rich stroma resembling that of CAF, the odontogenic epithelial component in POT is predominantly localized at the periphery of the lesion, with only a few scattered epithelial islands present within.¹⁷

Central ameloblastic fibroma can mimic a dentigerous cyst clinically and radiographically, especially when associated with an impacted tooth or when the pericoronal region is involved. The provisional diagnosis for the current case was dentigerous cyst as well. The distinction between both can be made under the microscope, as a dentigerous cyst will present with a 2–3 layer thick lining and lacks the characteristic odontogenic epithelial strands and immature cell-rich stroma.¹⁸

Differentiating from unicystic ameloblastoma is another challenge due to similar clinical and radiological appearances. The maturity of the stroma should be considered while differentiating both, in addition to the cell-rich myxoid nature with an embryonic appearance of CAF.¹⁹

Differentiation from calcifying odontogenic cyst (COC) can be made histologically, as COC will present with foci of calcification and ghost cells, whereas these will be absent in a CAF.²⁰

Here, we are presenting a clear case of a cyst that has the same lining as the epithelial component of AF and is directly connected to classic AF areas at the cyst wall, which, in our opinion, is best described as CAF.

Management and Prognosis

Due to the scarcity of cases reported in the literature, there has been no well-defined management protocol for CAF. However, the current case has presented a comprehensive interdisciplinary approach involving pediatric dentists, oral and maxillofacial surgeons, and oral pathologists and microbiologists working together in a staged management plan. This approach entails a thorough clinical and radiological assessment, histological analysis for confirmatory diagnosis, surgical excision followed by subsequent obturator placement, and a 2-year follow-up period to ensure the nonrecurrence of the lesion.

This approach has been described in detail for the first time, providing valuable insight into the management of CAF. The interdisciplinary approach emphasizes the importance of collaboration among different specialties in the diagnosis and treatment of CAF, which is crucial for achieving optimal patient outcomes. The successful implementation of this approach in the present case can serve as a valuable reference for future cases of CAF.

CONCLUSION

Although the current report is limited to one case, it adds to the complexity of the differential diagnosis of odontogenic lesions and precautions to be exercised in management. Cystic ameloblastic fibroma has been rarely reported in the literature; this is the first case reported in the Asian population and only the second case reported in the under-10-year age group. The present report also delineates the management protocol in the younger age group with mixed dentition for CAF.