GRANULAR-CELL AMELOBLASTOMA WITH METASTASIS TO THE LUNGS: REPORT OF A CASE AND REVIEW OF THE LITERATURE

Ameloblastoma and Intracranial Involvement: The Current Challenge of the Radical Surgical Treatment. Comprehensive Review of the Literature and Institution experience

Background

Ameloblastoma (AMBL) is an odontogenic tumor, considered to be benign, but aggressive, whose principal risk is a recurrence. The growth can be enormous, and it can extend into the intracranial compartment with serious consequences.

Purpose

The intracranial involvement of AMBL is rare, and it may require an extensive surgery. Although it is a rare condition for the neurosurgeon to treat, knowing this condition can lead to a significant increase in survival for these patients.

Methods

A case of a 56-year-old woman presented with a history of recurrent left maxilla AMBL with intracranial extension and dural involvement of the anterior and medial cranial fossa is reported, followed by a systematic review of the literature with the aim to identify the best surgical treatment.

Results

A total of 32 cases were included in the qualitative analysis. Management is varied and often not described, resulting in an almost complete lack of information and indications for treatment. Radical surgery tends to yield the best outcomes, and it is recommended to have adequate surgical margins when possible.

Conclusions

Intracranial involvement from AMBL compartment is an uncommon manifestation of this rare pathology, but which deserves to be treated in a multidisciplinary way in order to ensure maximum surgical radicality. Recurrence reflects failure of the primary surgical resection. If recurrence is the major consideration, surgeons are encouraged to select radical surgery. Whenever a follicular-type maxillary AMBL is diagnosed, it is advisable to check for intracranial spreading and distant metastases during follow-up.

Treatment efficacy and prognosis of pulmonary metastasizing ameloblastoma: a systematic review

The aim of this review was to integrate the current literature into a comprehensive evaluation of pulmonary metastasizing ameloblastoma (MA). Related articles, published since January 2000, were reviewed. The PubMed, Embase, Cochrane Database of Systematic Reviews, and Web of Science databases were searched based on the PRISMA guidelines. Twenty-four studies, including 28 case reports, met the eligibility criteria. The mean ± standard deviation disease-free interval after primary treatment was 12.1 ± 9.3 years. Adjuvant therapy (surgery and chemoradiotherapy) is considered appropriate for pulmonary MA patients presenting with rapid progression or apparent pulmonary symptoms. The proportion of patients undergoing simple follow-up (observation) has increased rapidly in the past 10 years. Meanwhile, among the three treatment groups (observation, surgery, and adjuvant therapy), no significant difference was found in the efficacy (P = 0.081) or progression-free survival (P = 0.263). The 5-year and 10-year overall survival rates were 72.4% and 52.8%, respectively. This study provides insights that could help surgeons with the management of patients presenting with pulmonary MA.

An unusual presentation of an odontogenic tumor: A diagnostic quandary

Squamous odontogenic tumor (SOT) is a rare benign neoplasm and may be located to multiple sites in the oral cavity mouth. As per the literature, there have been <50 reported cases. The tumor is often asymptomatic, although it can present with symptoms of pain and tooth mobility. Peripheral odontogenic tumor is a rare entity derived from either epithelial or mesenchymal portions of the tooth-forming apparatus. Lesions are common to gingiva and alveolar mucosa. Peripheral granular cell ameloblastoma (GCA) is considered to be even rarer. The purpose of the study is to report a case of SOT with a synchronous association with peripheral GCA of cystic nature in the mandible. The occurrence of SOT with ameloblastoma has not been reported as per the literature search.

Ameloblastoma with distinctive granular cell pattern: an 8 case study

Ameloblastoma with granular cell pattern (AGC) is classified as an unusual histological subtype of solid/multicystic ameloblastoma, characterized by granular changes in stellate-like cells located within the inner portion of the epithelial follicles. Studies have revealed that lysosomal overload causes cytoplasmic granularity; however, the mechanism involved remains poorly understood. Here we report on eight cases of granular cell ameloblastoma, in the posterior region of the mandible. The age of the patients included in this case series ranged from 35 -64 years old and 87.5% of cases occurred in non-Caucasians, with a slight gender predilection for men (62.5%). There was no evidence of recurrence, and the majority of the cases were treated with surgical resection (87.5%). All tumors displayed histopathological features consistent with the diagnosis of ameloblastoma with granular cell pattern.

Aggressive granular cell ameloblastoma: Report of a rare case

Granular cell ameloblastoma is a slow growing odontogenic ectodermal tumor. The tumor shows typical ameloblastoma with the cells showing eosinophilic granularity. This variant of ameloblastoma is aggressive with high recurrence rates. We report a case of aggressive ameloblastoma of granular cell variant.

Massive granular cell ameloblastoma with dural extension and atypical morphology

Ameloblastomas are rare histologically benign, locally aggressive tumors arising from the oral ectoderm that occasionally reach a gigantic size. Giant ameloblastomas are a rarity these days with the advent of panoramic radiography in routine dental practice. Furthermore, the granular cell variant is an uncommon histological subtype of ameloblastoma where the central stellate reticulum like cells in tumor follicles is replaced by granular cells. Although granular cell ameloblastoma (GCA) is considered to be a destructive tumor with a high recurrence rate, the significance of granular cells in predicting its biologic behavior is debatable. However, we present a rare case of giant GCA of remarkable histomorphology showing extensive craniofacial involvement and dural extension that rendered a good prognosis following treatment.

Granular cell type of a unicystic ameloblastoma: An unusual case and review of the literature

Ameloblastomas are locally invasive tumors of odontogenic epithelial origin. They have been categorized broadly into three biologic variants: solid, cystic (unicystic) and peripheral, of which only 13% of all cases are unicystic. Although rare in unicystic or cystic ameloblastoma, granular cell change in ameloblastoma is a recognized phenomenon. Here we present a distinctive case of cystic ameloblastoma with an unusual histopathological pattern along with an added emphasis on its review.

Ameloblastic carcinoma: A clinicopathologic dilemma - Report of two cases with total review of literature from 1984 to 2012

Ameloblastic carcinoma (AC) is a rare primary odontogenic tumor that has histological features of both ameloblastoma and carcinoma. A total number of 92 case reports speak about its rare incidence, affecting mostly the mandible as a locally destructive lesion. The maxilla is affected even more rarely as only 35 cases have been reported until 2012 in scientific literature. The clinical course of AC is generally aggressive, with extensive local bone destruction. The most common clinical features include swelling, pain, trismus, significant bone resorption with tooth mobility, dysphonia and intraoral fistula. We report two cases of AC with aggressive behavior.

Endoscopic transnasal resection of ameloblastoma with intracranial extension

Ameloblastoma is a rare odontogenic tumor with characteristics of epithelial tissue that produces enamel for the developing tooth. This lesion is generally considered benign, but has malignant forms that invade locally and metastasize. We present a 60-year-old man with maxillary ameloblastoma that after multiple recurrences developed intracranial extension with dural involvement of the middle cranial fossa and was treated by endoscopic transnasal resection followed by radiation therapy. Our technique and intraoperative findings are described with a review of the literature on intracranial ameloblastoma. This patient represents a unique account of endoscopic transnasal resection being utilized in the treatment of intracranial extension of ameloblastoma and demonstrates potential for application in similar cases.

Granular cell ameloblastoma: enigmatic cells in an unusual neoplasm

An unusual granular variant of ameloblastoma presenting as a mandibular mass in a 43-year-old woman is described. These visually striking tumors display unusual and inconsistent immunohistochemical staining patterns although differential diagnosis from other granular cell lesions of the head and neck is usually not problematic.

Metastasizing granular cell ameloblastoma

Ameloblastoma is a slow growing odontogenic epithelial tumor of jaw. It accounts for 1% of all tumors and cysts arising in maxilla and mandible. Although it is locally invasive and has a marked tendency to recur, metastasis is rare. Of the various histological patterns of ameloblastoma, the granular cell type is extremely rare accounting for 4% of ameloblastomas. We report a case of granular cell ameloblastoma with metastasis to the cervical lymph node presenting in a 40-year-old Indian female.

Granular cell ameloblastoma showing desmoplasia

Our case of ameloblastoma had a surprisingly long 25 year history, with abnormally large dimensions, a multilocular diffuse-mixed radiographic picture, and was histopathologically diagnosed as granular cell ameloblastoma with desmoplasia. To the best of our knowledge, this is the first ameloblastoma ever reported, that has shown combined features of granular cells, desmoplasia, ameloblastic follicles, plexiform, and acanthomatous patterns. The nature of granular cells in this type of tumor and the significance of their presence have also been reviewed. From the studies on ameloblastomas to date, it seems that the old belief that granular cell ameloblastoma is the most aggressive variant of ameloblastoma is a myth, and in all probability, granular cells are just a transitional or matured phase in the life cycle of ameloblastomas, starting with normal stellate reticulum-like cells, leading to a production of granules and finally leading to degeneration and formation of cystic areas.

Investigation of basement membrane proteins in a case of granular cell ameloblastoma

Granular cell ameloblastoma is a rare, benign neoplasm of the odontogenic epithelium. A case of massive granular cell ameloblastoma in a 44-year-old Thai female is reported. Histopathological features displayed a follicular type of ameloblastoma with an accumulation of granular cells residing within the tumor follicles. After treatment by partial mandibulectomy, the patient showed a good prognosis without recurrence in a 2-year follow-up. To characterize the granular cells in ameloblastoma, we examined the expression of basement membrane (BM) proteins, including collagen type IV, laminins 1 and 5 and fibronectin using immunohistochemistry. Except for the granular cells, the tumor cells demonstrated a similar expression of BM proteins compared to follicular and plexiform ameloblastomas in our previous study, whereas the granular cells showed strong positivity to laminins 1 and 5 and fibronectin. The increased fibronectin expression in granular cells suggests a possibility of age-related transformation of granular cells in ameloblastoma.

Malignant ameloblastoma: concurrent presentation of primary and distant disease and review of the literature

Malignant ameloblastoma is a rare tumor of odontogenic origin with a metastatic focus. Distant metastatic disease is found most commonly in the lungs. A review of the literature shows that most cases of malignant ameloblastoma involve a disease-free period from primary tumor extirpation to the discovery of metastasis. This report describes the case of a 56-year-old man presenting with ameloblastoma of the maxilla and a solitary pulmonary metastasis concurrently. This represents a rare case in which there is a simultaneous diagnosis of primary ameloblastoma and a metastatic lesion. Appropriate workup for ameloblastoma includes surveillance for metastatic disease. Surgical resection of primary and distant disease is recommended. Chemotherapy and radiation may play a role in palliation when resection of metastatic disease is not feasible.

Neuro-ophthalmologic Aspects of Ameloblastoma

Ameloblastomas are histologically benign tumors derived from the odontogenic apparatus. Although these tumors are locally invasive, they rarely invade the paranasal sinuses, orbits, or intracranial cavity, and, thus, they rarely produce ophthalmologic signs and symptoms. In this report, we describe the neuro-ophthalmologic features of three patients with chronically aggressive ameloblastoma. Two of the patients developed a progressive and recurrent orbital apex and cavernous sinus syndromes. One of these patients is, to our knowledge, the first patient described with orbital and cavernous simus involvement by an ameloblastoma initially arising in the mandible. The other is only the second case described with bilateral orbital involvement. The third patient in this series developed a trigeminal sensory neuropathy as the only sign of the tumor. Although ameloblastomas are benign, slowly growing tumors, they may, often over a long period of time, cause significant neuro-ophthalmologic and orbital manifestutions that can only be partially ameliorated by surgery.

Cystic granular cell ameloblastoma

Ameloblastoma is a locally aggressive benign epithelial odontogenic tumor, while unicystic ameloblastoma is a relatively less aggressive variant. Although rare in unicystic or cystic ameloblastoma, granular cell change in ameloblastoma is a recognized phenomenon. The purpose of the present article is to report a case of cystic granular cell ameloblastoma in 34-year old female.

Clinicostatistical study of ameloblastoma treatment

The purpose of this study was to investigate the treatment of 190 cases of ameloblastoma in our department from 1966 to 1994. The statistical results with regard to age, sex and region agreed with those of other investigators. Thirty-five of 43 (81.4%) cases underwent enucleation in 1960s, but the sixteen of 27 (59.3%) cases underwent partial resection of mandible in 1990s. The defect of mandible was reconstructed with iliac bone grafting since 1968, grafts with a mixture of iliac blocked bone and PCBM (particulate cancellous bone and marrow) have been used since 1975. Grafting of the inferior alveolar nerve with the great auricular nerve to the defect has been performed in our department since 1977. Recently, technique involving pull-through of the inferior alveolar nerve bundle has been used in our department. When the reconstruction method for the mandible and nerve has been established, it becomes possible to operate radically and positively. Recurrence occurred in 17 cases after the primary enucleation. It is thought that the primary treatment of ameloblastoma must be as radical as possible. It appears to be necessary to observe progress and perform follow-up in cases of ameloblastoma for more than ten years, because there was one recurrence at 9 years and 4 months after the first operation. In fact, three quarters of our cases were lost to follow-up. Such losses can problems in confirming recurrence and responding rapidly.

Recurrent ameloblastoma of the mandible

Ameloblastoma is an agressive locally recurring neoplasm of odentogenic epithelium. Here we describe a case of mandibular ameloblastoma with 12 yrs. history of local recurrences followed with history of excision twice (10 yrs. and 7 years back).

Atypical ameloblastoma: report of 3 cases and a review of the literature

This paper presents 3 atypical ameloblastomas which had a fatal outcome. One had histological features indicative of malignancy but without metastasis, another developed pulmonary metastasis and the third died of extensive infiltration of the skull base. The features of malignant ameloblastoma are discussed and reported cases of malignant ameloblastoma between 1966 and 1993 are reviewed.

Pulmonary metastatic disease in ameloblastoma

Ameloblastoma is a rare disease of odontogenic origin with indeterminate metastatic potential. The first site of metastatic disease is usually the lung. We report aggressive surgical treatment of a patient with bilateral disease with five subsequent recurrences. A review of the literature suggests that in the absence of effective chemotherapy or radiation, surgery should be considered the treatment of choice for metastatic ameloblastoma confined to the lung.

Doubling time of ameloblastoma metastasizing to the lung: report of two cases

Two cases of malignant ameloblastoma with metastases to the lungs are reported. One originated in the mandible and the other in the maxilla. The doubling time of the metastatic lesions to the lungs were calculated according to Collins' method, and ranged from 129 to 201 days.

Ameloblastic carcinoma. Report of an aggressive case and review of the literature

Odontogenic carcinomas of the jaws are classified as malignant ameloblastoma, ameloblastic carcinoma or primary intraosseous carcinoma. Because these lesions are extremely rare, microscopic diagnosis is difficult. An aggressive case of ameloblastic carcinoma of the mandible is presented. In spite of radical surgery and radiotherapy, the patient expired eight months following initial diagnosis. - A review of the literature seems to indicate that so called simple ameloblastomas rarely can dedifferentiate and metastasize following multiple inadequate surgical procedures. Although radical surgery is not necessary, local excision should be thorough. - Ameloblastic carcinoma and primary intraosseous carcinomas may be histogenetically similar. They are highly malignant tumours which should be treated aggressively. Metastasis is common and prognosis is poor.

Pulmonary metastases from ameloblastoma of the mandible treated with cisplatin, adriamycin, and cyclophosphamide

A case of delayed pulmonary metastases from an ameloblastoma of the mandible, which occurred 20 years after surgical resection of the primary tumor but with no recurrence at the primary site, is reported. Combination chemotherapy using cisplatin, adriamycin, and cyclophosphamide has produced a very good clinical and radiologically documented response in this case.

Metastasizing ameloblastoma

A case of malignant ameloblastoma with widespread, indolent metastases is reported and 42 previously published cases of metastasizing ameloblastoma are reviewed. The disease-free interval (DFI) between diagnosis of tumor and appearance of metastasis in 43 patients is 9 years. The median survival time after metastasis is 2 years. Most metastases were in the lung. Although the biologic behavior of ameloblastomas cannot be predicted on the basis of morphology, metastasis appears to follow multiple recurrences. Early adequate resection of the primary to avoid repeated surgical procedures is advocated to prevent tumor spread. Surgical removal is preferred for treating metastasis. Although the response to radiation cannot be predicted, radiation should be used to treat lesions not amenable to surgical removal. Disseminated ameloblastoma does not appear to respond to chemotherapy.

Ameloblastic carcinoma: a clinicopathologic study and assessment of eight cases

The term ameloblastic carcinoma is differentiated from the term malignant ameloblastoma and is defined as an ameloblastoma in which there is histologic evidence of malignancy in the primary tumor or the recurrent tumor (or metastasis), regardless of whether it has metastasized. Eight cases of ameloblastic carcinoma from the Armed Forces Institute of Pathology (AFIP) are reported. The mean age of patients was 30.1 years, with no sex predilection noted. Seven cases involved the mandible and one involved the maxilla, with the posterior regions favored. The most common sign was swelling, although pain, rapid growth, trismus, and dysphonia also occurred. Lesions characteristically were evident as ill-defined destructive radiolucencies, with occasional radiopacities noted. Histologic features generally resembled those of conventional ameloblastoma but with cytologic features of epithelial malignant disease. The clinical course was uniformly aggressive with extensive local destruction and spread, frequent recurrences, and one case of neck node metastasis. The nomenclature and classification of odontogenic carcinomas are discussed, as well as entities that should be included in the differential diagnosis. Further reporting of ameloblastic carcinoma is encouraged.

Mandibular ameloblastoma with intracranial extension and distant metastasis

A case of mandibular ameloblastoma which invaded intracranially through the skull base and developed distant metastasis to the femur is reported. The intracranial extension of the tumor was partially removed three times and the metastasis of the femur was curetted. The remaining tumor temporarily responded to chemotherapy, but the patient died of intracranial tumor regrowth. The period from the initial treatment of the mandibular tumor to death was 21 years.

Biology of metastasizing ameloblastoma

The present report of a malignant metastasizing ameloblastoma and a critical review of literature was undertaken in an attempt to better understand the biological potential and behavior of this rare tumor and thus to facilitate its clinical management. Most of the 26 patients with a proven malignant ameloblastoma including the present case had developed multiple recurrences. The lung was the most frequent metastatic site (88%) followed by regional lymph nodes (27%). Furthermore metastases were observed in some cases in the bone, brain, kidney, small intestine and liver. The interval between diagnosis of tumor and manifestation of metastases was long with a median of 11.1 years. The average survival time was 13.1 years. By contrast, the interval between diagnosis of metastatic disease and death was relatively short (median: 2.6 years). The histologic and cytologic pattern of malignant ameloblastoma and of its metastases was not significantly different from that of non-metastatic ameloblastoma. Because of the lack of morphological criteria of malignancy the biological behavior of ameloblastomas cannot be predicted. It is difficult to be certain which factors are important in the delayed induction of metastases. It is suspected that ameloblastomas possess an inherent low grade malignancy which is stimulated by multiple recurrences. It is further assumed that the metastatic tumor cells have a slow growth rate resulting in late clinical manifestation of metastases. When lung metastases occur we recommend their surgical removal in order to prolong live expectancy or even to obtain a curative effect.

Maxillary ameloblastoma with orbital invasion. A clinicopathologic study

A 72-year-old white man presented to Massachusetts Eye and Ear Infirmary with proptosis of the right eye. Computerized tomography (CT) scan revealed a mass which filled the right maxillary sinus and invaded the orbital and middle cranial cavities. Six years earlier, the patient had excision of an ameloblastoma of the right maxillary antrum. The tumor recurred, requiring maxillectomy, local radiotherapy and finally exenteration. Ameloblastoma is a relatively rare epithelial tumor arising from embryonal tooth elements. It is locally invasive and recurrent but rarely metastasizes and extension to the orbit is extremely unusual. The clinical features, histopathologic findings and treatment of this tumor are discussed. Differential diagnosis of jaw tumors, which may invade the orbit, is reviewed.

Ultrastructural and histochemical studies of granular-cell ameloblastoma

Four cases of granular-cell ameloblastoma were studied by light and electron microscopy, histochemistry and electron enzyme histochemistry. Microscopically, granular cells commonly occurred in a follicular pattern, but, in one case, they were in a plexiform pattern. The high activity of acid phosphatase and electron microscopic features revealed that the cytoplasmic granularity was ascribed to the high content of lysosomes. It was speculated that granular-cell ameloblastoma occurs due to the altered dysfunction of tumor cells, and the age factor is related to the pathogenesis of this tumor.

Malignant ameloblastoma or ameloblastic carcinoma

The World Health Organization defines malignant ameloblastoma as a lesion exhibiting features of an ameloblastoma in primary and metastatic growths. To cases collected from the literature we have added two of our own cases in which features of an ameloblastoma were coupled with malignant behavior. It was noted that the diagnosis of "malignant ameloblastoma" is at present used in a rather indiscriminate way, resulting in the grouping of lesions that exhibit considerable differences in biological behavior and histomorphology. This might be due to the fact that the WHO classification emphasizes metastasis as a diagnostic criterion but is rather vague in defining histopathologic aspects. It is advocated that the term malignant ameloblastoma be reserved for those lesions that, in spite of a seemingly innocuous histology, have given origin to metastatic growths, while the WHO classification should be modified to include ameloblastic carcinoma as a diagnostic term for lesions that combine features of an ameloblastoma with a less-differentiated histomorphology.

Immunocytochemical demonstration of intermediate filaments in a granular cell ameloblastoma

The nature and location of intermediate filament proteins (IFP) may provide new insights into the origin and differentiation of neoplastic cells. An immunofluorescent study of these IFP in a case of a granular cell ameloblastoma revealed that all tumor cells contained the IFP keratin. Some granular cells, however, also contained the IFP vimentin, which is considered specific for mesenchymal tissues only. The implications of these observations are discussed. Study with monoclonal antibodies indicated the origin of the ameloblastoma from non-keratinized squamous epithelium. A comparison of the anti-keratin immunofluorescence pattern of the ameloblast-like cells in the present tumor with ameloblasts in the tooth germ revealed no similarities, indicating that despite some resemblance of the peripheral columnar cells to ameloblasts, these cells differ in other aspects.

Metastatic ameloblastoma of the skull

A rare case of a metastatic ameloblastoma of the skull in a 29-year-old woman is reported. An ameloblastoma of the left mandible underwent histological malignant transformation following repeated operations and eventually metastasized to the left temporoparietal region of the skull. The skull tumor showed osteolytic change and marked vascularity in roentgenological examinations. It was removed totally. The histological findings were similar to those of the tumor of the left mandible. The route of the metastasis was considered to be via the left external carotid artery.

Ultrastructural study of granular cell ameloblastoma

A granular cell ameloblastoma occurring in the anterior mandible of a 49-year-old woman has been studied both histologically and ultrastructurally. Histologically the tumor in this case showed a mixed type of follicular, granulal cell, and acanthomatous type of ameloblastoma. Many granular cells seemed to gather around the periphery of each tumor island. Electron-microscopically the cytoplasmic granules were measured as approximately 0.6 mu in diameter, and were surrounded by limiting membrane. Most of these granules revealed high electron density and their contents showed various patterns--osmiophilic homogeneous, fingerprint, and small particles--and were identified as lysosomes. However, no enamel matrix precursor was identified in either lysosome or cytoplasm. All the granular cells showed regular nuclei and no degeneration. Though lysosomes might play a role of autophagy and of remodeling the cytoplasm, its presence seems to have an active function in tumor cells, as opposed to the aging or degenerating function.

Central granular-cell tumor of the jaws (the so-call granular-cell ameloblastic fibroma)

Four cases of central granular-cell tumor of the jaws were evaluated to determine the clinical parameters of the lesion, and one of these cases was examined with the electron microscope to investigate the nature of the granular cells. The average age of the patients at the time of treatment was 55 years; all four patients were women. Three of the lesions originated in the mandible, and one in the maxilla. Follow-up studies revealed no recurrences. Electron microscopic examination of one case revealed that the granular cells contained many lysosome-like particles and that these cells are identical to those found in the granular-cell myoblastoma.