Journal of Cancer Research and Therapeutics Medknow Publications on behalf of the Association of Radiation Oncologists of India (AROI) ISSN: 0973-1482 EISSN: 1998-4138 Vol. 6, Num. 4, 2010, pp. 588-590

Journal of Cancer Research and Therapeutics, Vol. 6, No. 4, October-December, 2010, pp. 588-590

Letter to the Editor

Ameloblastoma mimicking as mucoepidermoid carcinoma on cytology

Mani Makhija, Sonal Sharma, Mrinalini Kotru

Department of Pathology, University College of Medical Sciences, Delhi, India

Correspondence Address: Sonal Sharma, Department of Pathology, University College of Medical Sciences, Shahdara, Delhi-110095, India, sonald76@rediffmail.com

Code Number: cr10148

PMID: 21358111

DOI: 10.4103/0973-1482.77093

Sir,

A mass in the salivary gland region often presents a diagnostic challenge with regard to its site of origin (salivary versus non-salivary), benign or malignant nature, and tissue-specific diagnosis.

A 30-year-old female presented with a painless left submandibular swelling. The patient gave a history of surgery eight years back in the same region. Previous surgical notes and histopathology sections could not be procured for a review. On examination a submandibular swelling was seen measuring 4×3 cm.

The smears were hypercellular and showed a mucoid background with debris. There were tight clusters and sheets of hyperchromatic epithelial cells [Figure - 1]. Keratinized squamous cells were seen among cells with intercellular cytoplasmic vacuoles containing mucin which stained metachromatically with MGG [Figure - 2]. Mitotic figures were absent. On the basis of these cytomorphorphological features from a submandibular swelling with history of previous surgery, a diagnosis of recurrent mucoepidermoid carcinoma was considered.

Subsequent excision of the mass was carried out. Cut section was nodular and showed mucoid material oozing from the cut surface. Sections showed a circumscribed soft tissue tumor mass consisting of nests and aggregates of basaloid cells showing peripheral palisading and squamous metaplasia. A loose meshwork of stellate reticulum was seen in the center [Figure - 3]. On the basis of classical histopathological findings a diagnosis of ameloblastoma was suggested.

Radiological review showed that a part of the mandible had been removed as a part of previous surgery. The post-operative course of the patient was uneventful. The patient was followed up for six months and is doing well.

Ameloblastoma is the most frequent epithelial odontogenic neoplasms constituting about 1% of jaw tumors. ^[1] Ameloblastoma has invasive property and a tendency for local recurrence.

The differential diagnosis of ameloblastoma on cytology includes mucoepidermoid carcinoma, adenoid cystic carcinoma, odontogenic tumors, myxomas, giant cell lesions and pilomatrixoma. In our case the presence of mucoid background, mucin vacuoles and squamous cells misled the diagnosis of mucoepidermoid carcinoma. Choudhary et al. also agree that cellular qualities of ameloblastoma may superficially resemble intraosseous salivary gland neoplasms among other odontogenic cysts. ^[2] And since in our case the lesion presented as a soft tissue mass a differential of a more common salivary tumor was offered initially. However on retrospect, it was noticed that these squamous cells did not show any nuclear pleomorphism. These anatomizing squamous cells actually constitute the stellate reticulum like component of ameloblastoma. The large, polygonal, distinct cytoplasm of these cells is described as basophilic and contains occasional small vacuoles. Moreover ameloblastomas with cystic change may provide samples with myxoid background material, abundant macrophages and leukocytes without lesional cells indicative of cystic degeneration. ^[3]

However, the presence of peripheral palisading, presence of spindle cells and the lack of nuclear pleomorphism in squamous cells should lead to the correct diagnosis of ameloblastoma. Ameloblastomas have sufficiently distinctive cytologic features to make the diagnosis by FNAC possible.

References

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