Peripheral ameloblastoma in-situ: an evidential fact of surface epithelium origin

Intraoral Basal Cell Carcinoma of Soft Palate: A Diagnostic Dilemma and Review of Literature

Basal cell carcinoma is the most common cancer worldwide. Most of basal cell carcinoma can be detected in the early stages and are generally well controlled with local resection. Despite the high incidence of BCC, intramucosal BCC is a very rare clinical entity. We hereby present a rare case report of pigmented BCC on soft palate and review the literature of this entity.

Current practice in the management of peripheral ameloblastoma: a structured review

Ameloblastoma is the most common benign, but locally destructive, epithelial odontogenic tumour. Peripheral ameloblastoma may involve soft tissues without invasion or involvement of bone. The aim of this structured review was to evaluate the literature and guide clinical management. Three online databases were searched for relevant studies: Medline, EMBASE, and Ovid Evidence-Based Medicine, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. A total of 520 papers were initially identified, and after exclusions were applied, 45 were included. Conservative surgical excision was the treatment of choice. There was no consensus in relation to the extent of the surgical margins required. The management of peripheral ameloblastoma appears to favour conservative excision with narrow margins of normal tissue. Follow up of at least 10 years is recommended to monitor for recurrence.

The dilemma of extensive unilocular radiolucent lesions of the jaws - value of immunohistochemistry as a diagnostic marker and prognostic Indicator

INTRODUCTION

Large Unilocular radiolucent lesions of the jaws often present a dilemma to both, the Oral Pathologist and the Maxillofacial surgeon with regards to their accurate diagnosis as well as their most appropriate treatment modality. A precise identification as to whether the lesion is a cyst or a tumor is imperative before any treatment is instituted. Once the correct diagnosis and likely prognosis are established, a management protocol can be planned which will completely eliminate the lesion, while at the same time, ensure least possible morbidity for the patient, such as pathological jaw fractures, persisting neurological deficits, esthetic deformity, functional debility, recurrence/persistence of the lesion, etc. AIM & OBJECTIVES: To establish the value of Immunohistochemistry (IH) as a Diagnostic marker and Prognostic indicator for extensive Unilocular radiolucent lesions of the jaws. To assess its role as an adjunct to Histopathological Examination (HPE) in distinguishing Odontogenic tumours from the cysts, by identifying the former using IH Tumor Markers; and in aiding in selection of the most appropriate and effective treatment option for each of such ambiguous lesions, based on their prognosis as indicated by the expression of lH Cell Proliferation Markers.

MATERIALS AND METHOD

Thirty cases of large Unilocular Radiolucent lesions of the jaws (Maxilla/Mandible) were managed over a period of three years. Histopathological examination (HPE) and Immunohistochemical (IH) analysis were carried out of the biopsy specimens in all the cases. Calretinin, an Immunohistochemical Tumor marker, was used to distinguish between Odontogenic cysts and tumours. Ki-67 and Proliferating Cell Nuclear Antigen (PCNA), Immunohistochemical Cell Proliferation markers, provided information on the aggressive potential of the lesions. On the basis of the above information, an appropriate management protocol was established for each of these different lesions. Nerve sparing enucleation and curettage was employed for the established cases of Odontogenic Cysts; Enucleation and curettage, peripheral ostectomy, followed by chemical cauterization was employed for the Unicystic Ameloblastomas and other Odontogenic tumours with a low Ki-67 and PCNA Proliferation Index (PI)/Labelling index (LI ≤ 3); Marginal resection was carried out for the tumours with a higher Labelling Index (LI >3 ≤5), and Segmental resection (including partial/complete Maxillectomy, Hemimandibulectomy with/without disarticulation) for the aggressive pathologies with high Labelling Index (LI > 5).

RESULTS

Of the thirty cases of large Unilocular radiolucent lesions of the Maxilla and Mandible, thirteen were diagnosed as Dentigerous cysts, one as Dentigerous cyst showing Ameloblastomatous transformation; two as Unicystic Ameloblastomas, one as the Mural variant of Unicystic Ameloblastoma; four as Follicular Ameloblastomas, two as Plexiform Ameloblastomas; four as Acanthomatous Ameloblastomas; one as Ameloblastic Fibroma and two as Adenomatoid Odontogenic Tumours. The predictive and prognostic indication of the Immunohistochemical markers correlated well with the post treatment findings.

CONCLUSION

In cases of extensive Unilocular lesions of the jaws, where ambiguity often exists in both diagnosis and appropriate treatment plan to be employed, Immunohistochemistry can serve as an invaluable tool in establishing the precise diagnosis, guiding the treatment plan, as well as indicating the likely prognosis of these lesions.

Peripheral ameloblastoma of gingiva with cytokeratin 19 analysis

A 42-year-old woman presented with a gingival mass in the lingual vestibule of the mandibular incisor premolar region. On intraoral examination, the swelling was non-tender and firm. Surgical excision was carried out and subsequent histopathological examination revealed areas resembling ameloblastoma-like and basaloid areas with atypical features suggestive of basal cell carcinoma. Immunohistochemical analysis was carried out to ascertain the origin of the lesion.

Peripheral ameloblastoma of the upper gingiva: Report of a case and literature review

According to the 2005 histological classification of odontogenic neoplasms by the World Health Organization, ameloblastoma is a benign, locally invasive epithelial odontogenic tumor of putative enamel organ origin. There are four distinct subgroups in which this neoplasm can be gathered: the solid/multicystic type, the unicystic type, the desmoplastic and the peripheral type. Peripheral ameloblastoma is believed to be the rarest subgroup, making up for 2 to 10% of all ameloblastomas. From its first description by Kuru in 1911 to date, less than 200 cases of PA have been described in literature. PAs commonly affect the mandible, in the maxilla the most common location is the soft palatal tissue of the tuberosity area. The present report discusses a rare case of PA aroused in the gingiva of upper jaw in a 64-year-old woman. The treatment of the lesion and its immunohistochemical phenotype are described. A review of the literature is also performed, focusing on the epidemiological and pathological aspects of the lesions and their implications on the therapy.

Key words:Peripheral ameloblastoma, upper gingiva, ameloblastoma.

Intraoral basal cell carcinoma, a rare neoplasm: report of three new cases with literature review

Intraoral basal cell carcinoma (IOBCC) is an extremely rare entity that bears close microscopic resemblance to and is often confused with the peripheral ameloblastoma (PA). Basal cell carcinomas are thought to arise from pluripotential basal cells present within surface epithelium and adnexal structures, so theoretically they can arise within the oral cavity. Many of the early cases reported as IOBCC actually represent PA. Most of the well documented cases arise from the gingiva. The histologic features of basal cell carcinoma that help separate it from a PA include: tumor arising from surface epithelium, scattered mitotic figures and apoptotic cells, presence of mucoid ground substance and tumor infiltrating widely throughout the connective tissue and often exhibiting a prominent retraction artifact. Clinically IOBCC resemble carcinomas, compared to the benign and innocuous appearance of the PA and typically presents as surface ulcerations varying from rodent ulcer to an ulcerated erythroplakia appearance. This contrasts with the classic "bump on the gum" appearance of PAs with usually intact surface and appearing as small discrete, sessile, exophytic lesions. Importantly, the proliferative basaloid epithelium demonstrates positive immunoreactivity for the anti-epithelial antibody, Ber-EP4, a cell surface glycoprotein. The IOBCC has the potential for local recurrence and aggressive behavior and should be treated with wide surgical excision and close clinical follow up. We present 3 rare cases of IOBCC and discuss the salient histologic, immunohistochemical and clinical features.

Current concepts and occurrence of epithelial odontogenic tumors: I. Ameloblastoma and adenomatoid odontogenic tumor

Ameloblastomas and adenomatoid odontogenic tumors (AOTs) are common epithelial tumors of odontogenic origin. Ameloblastomas are clinico-pathologically classified into solid/multicystic, unicystic, desmoplastic, and peripheral types, and also divided into follicular, plexiform, acanthomatous, granular types, etc., based on their histological features. Craniopharyngiomas, derived from the remnants of Rathke's pouch or a misplaced enamel organ, are also comparable to the odontogenic tumors. The malignant transformation of ameloblastomas results in the formation of ameloblastic carcinomas and malignant ameloblastomas depending on cytological dysplasia and metastasis, respectively. AOTs are classified into follicular, extrafollicular, and peripheral types. Ameloblastomas are common, have an aggressive behavior and recurrent course, and are rarely metastatic, while AOTs are hamartomatous benign lesions derived from the complex system of the dental lamina or its remnants. With advances in the elucidation of molecular signaling mechanisms in cells, the cytodifferentiation of epithelial tumor cells in ameloblastomas and AOTs can be identified using different biomarkers. Therefore, it is suggested that comprehensive pathological observation including molecular genetic information can provide a more reliable differential diagnosis for the propagation and prognosis of ameloblastomas and AOTs. This study aimed to review the current concepts of ameloblastomas and AOTs and to discuss their clinico-pathological features relevant to tumorigenesis and prognosis.

Peripheral ameloblastoma: a case report and review of literature

Peripheral ameloblastoma, a rare and unusual variant of odontogenic tumour, comprises about 2–10% of all ameloblastomas. The extraosseous location is the peculiar feature of this type of tumour, which is otherwise similar to the classical ameloblastoma. This paper describes a case of peripheral ameloblastoma in a 67-year-old female affecting the lingual alveolar mucosa of the mandibular 32–34 region which was clinically diagnosed as pyogenic granuloma. This paper becomes important due to availability of all data, makeing it a well-documented case.

Cytopathologic features of secondary peripheral ameloblastic carcinoma: a case report

Peripheral ameloblastic carcinoma is an extremely rare odontogenic tumor derived from the remnants of dental lamina and/or mucosal epithelium of the oral mucosa. We present a case of secondary peripheral ameloblastic carcinoma of the mandibular gingiva. The patient was a 71-year-old man with gingival swelling and persistent bleeding. Exfoliative cytology revealed cohesive clusters composed of basaloid cells with nuclear atypia and various forms of keratinized cells of dysplastic squamous appearance. Some cell groups had a peripheral palisade. Histology of the biopsy and surgically removed specimens revealed characteristic features resembling squamous cell carcinoma, basal cell carcinoma, and benign follicles of ameloblastoma. These neoplastic structures, as well as proliferation and elongation of the mucosal epithelium, comprised an extensive network. The varied cytopathologic findings may be related to proliferation and transformation of basal cells of the mucosal epithelium toward ameloblastic carcinoma and variable squamous differentiation.

CD56 (NCAM) expression in ameloblastomas and other odontogenic lesions

AIMS

  Ameloblastomas recapitulate certain elements of tooth formation. CD56 is expressed by a variety of cells and is used in tumour diagnosis, but is also expressed in the enamel organ during tooth development. The aim of this study was to describe the expression of CD56 in odontogenic lesions with particular reference to the differential diagnosis of ameloblastoma and odontogenic keratocyst.

METHODS

  Cases were selected from the pathology archives at Glasgow Royal Infirmary, Glasgow, Royal Victoria Infirmary, Newcastle and Department of Diagnostic Sciences, Texas A&M Health Science Center Baylor College of Dentistry, Dallas. The study population included 38 ameloblastomas, 19 odontogenic keratocysts and a number of other odontogenic lesions, including nine compound odontomes. All sections were examined for CD56 immunoreactivity and the extent of staining was recorded.

RESULTS

  Thirty-seven of 38 (97%) ameloblastomas expressed CD56 on the cell membrane of peripheral cells in tumour nests (16 extensively, 21 focally). Immunoreactivity was lost in areas of inflammation, acanthomatous differentiation, in areas of cystic change and upon fusion with overlying surface epithelium. One odontogenic keratocyst expressed CD56 (5%, P < 0.0001). CD56 was expressed very focally in two odontomes, exclusively in stratum intermedium-like cells.

CONCLUSIONS

  CD56 expression in odontogenic epithelium is highly suggestive of ameloblastoma and can help in differentiating this from odontogenic keratocyst.

Intraosseous ameloblastoma

Ameloblastomas are benign slow-growing aggressive neoplasms with a poorly understood potential for rare metastasis. They are capable of reaching large sizes with extensive local bone erosion and destruction. They are composed of a mixture of ameloblastic epithelium and mesenchyme and arise from rests of outer and inner enamel epithelium and dental lamina. Microscopically, ameloblastomas are recognizable from their recapitulation of embryologic ameloblasts and stellate reticulum. There are 3 subtypes: the conventional or solid-multicystic variant, the unicystic variant, and the desmoplastic variant. Treatment planning for a given tumor includes consideration of location, primary versus recurrent, size, presence of cortical perforation, and age and health of the patient. Complete excision is recommended for conventional and desmoplastic variants. The unicystic variant requires additional subtyping to determine the best treatment approach.