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Medicina Oral, Patología Oral y Cirugía Bucal (Ed. impresa)

versão impressa ISSN 1698-4447

Med. oral patol. oral cir. bucal (Ed.impr.) v.10 n.3 Valencia maio-jul. 2005

 

Ameloblastoma. Diagnosis by means of FNAB. Report of two cases
Diagnóstico citológico de las recidivas tumorales de ameloblastoma: 
Presentación de dos casos clínicos

 

Artés Martínez MJ (1), Prieto Rodríguez M (1), Navarro Hervás M (2), Peñas Pardo L (1), Camañas Sanz A (3)
Vaquero de la Hermosa MC (4), Vera Sempere FJ (5)

(1) Médico Adjunto de Anatomía Patológica. Hospital Universitario La Fe. Valencia
(2) Médico Especialista de Anatomía Patológica. Hospital La Ribera. Alzira (Valencia)
(3) Jefa de Sección de Citopatología-PAAF. Hospital Universitario La Fe. Valencia
(4) Jefa de Servicio de Cirugía Máxilofacial. Hospital Universitario La Fe. Valencia
(5) Profesor Titular de Anatomía Patológica y Jefe de Servicio de Anatomía Patológica del Hospital Universitario La Fe.
Universidad de Valencia

 Address:
Prof. Dr. F.J. Vera-Sempere
C/ Daoíz y Velarde nº 8, 14
46021-Valencia
Tfno. 96 3862799, FAX: 96 1973089
E-mail: vera_fra@gva.es

Received: 1-02-2004 Accepted: 21-08-2004

 

Artés-Martínez MJ, Prieto-Rodríguez M, Navarro-Hervás M, Peñas-Pardo L, Camañas-Sanz A, Vaquero de la Hermosa MC, Vera-Sempere FJ. Ameloblastoma. Diagnosis by means of FNAB. Report of two cases. Med Oral Patol Oral Cir Bucal 2005;10:205-9.
© Medicina Oral S. L. C.I.F. B 96689336 - ISSN 1698-4447

 

SUMMARY

Introduction: Ameloblastomas are the most frequent odontogenic tumors of the maxilla. In spite of their benign cytohistological appearance, they behave as invasive recurring tumors, with the possibility of metastasis.
FNAB is a rapid, bloodless test that provides a pre-surgical diagnosis, thus, on occasions avoiding the need for diagnostic biopsies.
We present the cytological characteristics of two cases of jugal recurrences of mandibular ameloblastomas diagnosed by FNAB, as well as their cytohistological correlation.
Clinical cases: Two patients, a 36-year-old woman, and a 62-year-old male who both attended with mandibular swelling of a few months evolution. In both cases the first diagnostic approximation was the histological study of the tumoral mass, together with the radiological studies. Following therapeutic extirpation both cases recurred. The diagnosis of the recurrences was established cytologically by means of FNAB.
The cytologic smears revealed a granular background with isolated macrophages and giant multinucleate cells and an abundant epithelial cellularity of basaloid appearance arranged in cohesive groups forming images of peripheral palidasing, as well as small groups of squamous metaplastic cells.
Discussion: FNAB is considered to be a rapid, bloodless and reliable method for the diagnosis of ameloblastoma. The cytology of these tumors reveals components of the lesion that, in general, are sufficient for the diagnosis of ameloblastoma, especially in cases of recurrence.

Key words: Ameloblastoma, FNAB, recurrence.

RESUMEN

Introducción: Los ameloblastomas son los tumores odontogénicos más frecuentes del maxilar. A pesar de su aspecto citohistológico de benignidad, se comportan como tumores invasivos, recidivantes y con posibilidad de metastatizar.
La P.A.A.F. es una prueba rápida e incruenta que proporciona un diagnóstico prequirúrgico evitando, en ocasiones, tomas biópsicas destinadas al diagnóstico.
Presentamos las características citológicas de dos casos de recidiva yugal de ameloblastoma de rama mandibular diagnosticados por PAAF, así como su correlación citohistológica.
Casos clínicos: Dos pacientes, una mujer de 36 años y un varón de 62 años, que acuden por tumoración mandibular de escasos meses de evolución. En ambos casos, la primera aproximación diagnóstica fue –junto a los estudios radiológicos– el estudio histológico de la masa tumoral. Tras la extirpación terapeútica, ambos casos recidivaron. El diagnóstico de las recidivas fue establecido citológicamente mediante PAAF.
Las extensiones citológicas mostraron un fondo granular con aislados macrófagos y células multinucleadas gigantes y una abundante celularidad epitelial de aspecto basaloide dispuesta en grupos cohesivos configurando imágenes de empalizada periférica, así como pequeños grupos de células de metaplasia escamosa.
Discusión: La PAAF se considera como un método diagnóstico rápido, incruento y fiable en el diagnóstico del ameloblastoma. La citología de estos tumores revela los componentes de la lesión que, en general, son suficientes para llegar al diagnóstico de ameloblastoma, especialmente en casos de recidiva.

Palabras clave: Ameloblastoma, PAAF, recidiva.

INTRODUCTION

The maxillae, as with other bone structures, can become affected by different localized or widespread skeletal diseases. At the same time, the maxillary location of the dental structures can be the origin of numerous cystic or tumoral inflammatory lesions.

Ameloblastoma is the most frequent odontogenic tumor (1). It represents 1% of all mandibular lesions (cystic or tumoral). It derives from odontogenic epithelium, although it can also arise from cellular remnants of the enamel organ or of the basal layer of the oral mucosa (2).

Clinically, it frequently manifests as a painless swelling, which can be accompanied by facial deformity, malocclusion, loss of dental pieces, ulceration and periodontal disease (3,4). It appears with greater frequency in the third or fourth decade of life, although cases have been described in children (5).

Histologically, ameloblastoma is characterized by the proliferation of epithelial cells arranged on a stroma of conjunctive vascular tissue in locally invading structures that resemble the enamel organ at different stages of differentiation. Diverse histological patterns have been described (follicular, plexiform, acanthomatous, papilliferous-keratotic, desmoplastic, of granular cells, vascular and with dentinoid induction) (6,7). Two or more patterns are usually observed in the same tumor, although no evidence exists as to whether the different patterns provide a different prognosis.

It is an invasive and recurring tumor, the term malignant ameloblastoma being reserved only for those metastatic tumors that preserve the typical morphology of ameloblastoma (8).

FNAB is not usually the first diagnostic method in these lesions, probably due to the fact that an incisional biopsy is easily and rapidly carried out. Nevertheless, the cytological study, can be very useful in cases of metastatic disease or in the follow-up of possible recurrences (9,10).

The cytology reveals components of the lesion with a characteristic combination of epithelial cells of basaloid appearance, squamous metaplastic cells and cells resembling stellate reticulum; generally identified on a granular background. The finding of macrophages and giant multinucleate cells is quite common. These findings, in conjunction with the clinical and radiological information, are sufficient for a correct cytologic diagnosis of ameloblastoma (11).

The two clinical cases presented below illustrate the great benefit that can be obtained for these patients by a rapid and bloodless test (FNAB) that provides a pre-surgical diagnosis, on many occasions avoiding diagnostic surgery.

CLINICAL CASES

Case nº 1: A 36-year-old woman, with no previous history of interest, who came to the Maxillofacial Surgery Service with a progressively growing tumor on the left mandible, of 5 months of evolution.

The radiological exploration (X-Ray and CAT) showed a large right mandibular mass (third distal ramus ascendens) with an external and internal cortical break. The histological study of the biopsy revealed the existence of an ameloblastoma of mixed follicular-plexiform pattern. A therapeutic approach to the lesion was made, carrying out a left hemimandibulectomy.

After 4 years free of disease the patient presented again with a swelling on the left mandible protuding towards the oral cavity. On this occasion, the diagnosis was cytologic, carrying out two FNAB that confirmed the recurrence of ameloblastoma, the patient remaining free of tumoral disease at the present time (36 months).

Case nº 2: A 66-year-old male with precedents of type II diabetes mellitus, who came to the Maxillofacial Surgery Service with a tumor pertaining to the right mandible of 2 months evolution.

The radiology revealed a multicystic tumor in the retromolar trigonum of the right mandibula with involvement of the deep parotid lobe. The histological material proceeding from the marginal osteotomy carried out showed the existence of an ameloblastoma of mixed follicular-plexiform pattern. Following this first resection, the patient has suffered 5 recurrences up to the present time (July, 2003), affecting the masseter and pterygoid muscles as well as the palate, in spite of maintaining resection limits free of tumoral infiltration in all the surgical interventions. For all the recurrences, the first diagnostic approximation was an FNAB, this being sufficient for diagnosis in all the cases.

The cellularity obtained in both cases, in which a total of 6 punctures were practised (one in case nº 1 and five in case nº 2), was variable; isolated groups of monomorphic epithelial cells only being observed in the smears from the first case (fig.1). Nevertheless, the material aspirated in the punctures of case nº 2 showed, on all occasions, abundant epithelial cellularity on a granular background containing abundant macrophages, isolated giant multinucleate cells and small cellular groups with features of squamous metaplasia.

In both cases, the epithelial cellularity, consisted of monolayered plates of cells of basaloid appearance, with elongated hyperchromatic nuclei, no evident atypia and scant, poorly defined cytoplasm. The cellular arrangement was isolated as well as in cellular plates. The plates frequently presented a cellular peripheral palisade arrangement (fig.2), observing elongated cellular borders arranged in parallel and delimiting the outline of the plates.

In the first case, the histological study of the biopsy revealed the existence of an ameloblastoma of mixed pattern affecting the left mandibular ramus, having both follicular type areas - with the presence of nests covered by a single layer of columnars cells with subnuclear vacuoles and centred with stellate cells - and plexiform areas, made up of anastomosed cords and epithelial cells.

The histological pattern of the second case revealed a multicystic growth affecting the mandibula and right parotid (deep lobe) of predominantly follicular pattern.

DISCUSSION

Ameloblastoma is a benign, though locally invasive tumor, with a tendency to recurr - even after satisfactory resection. It is able to undergo either malignant transformation or even metastasis (8,9,10). It seems that recurrence depends on diverse factors, such as: multicystic character, the method of treatment of the primary lesion, extent of the lesion and site of origin. Now, the treatment of choice is a partial maxillectomy with a margin of 10-15 mm of healthy bone that includes the alveolar edge, the hard palate, the maxillary sinus mucosa and the lateral nasal wall (12).

At the cytological level it demonstrates some typical features, with a combination of epithelial cells of basaloid appearance, squamous metaplastic cells and cells with features of stellate reticulum, and likewise, the frequent presence of macrophages and giant multinucleate cells. On occasions, it can raise differential diagnostic problems with ameloblastic fibroma (another odontogenic tumor with radiological features on occasions similar to those of ameloblastoma) and with tumors of the salivary gland. Salivary tumors of intraosseous location are rare and represented, fundamentally, by adenoid cystic carcinoma, mucoepidermoid carcinoma and carcinoma of acinar cells, all with cellular and extracellular components ("balls" of metachromatic material, mucoid material, etc.), so typical that they do not generally give rise to differential diagnostic problems.

Both clinical cases presented here illustrate how cytology by FNAB, in a suitable clinico pathological context, facilitates the establishment of a differential diagnosis. In our opinion, it is a very useful tool in the diagnosis of recurrences of ameloblastoma, permitting a rapid, innocuous, economic and reliable diagnosis.

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