Oncocytoma of parotid gland: A rare case report

Oncocytoma of parotid gland ISSN: 2394-0026 (P)Case Report ISSN: 2394-0034 (O)Oncocytoma of parotid gland: A rare case report Annie Jain1, Gunvanti Rathod2* 1P.G. Student, Pathology Department, SBKS MI & RC, Sumandeep Vidyapeeth, Vadodara, India2Assistant Professor, Pathology Department, SBKS MI & RC, Sumandeep Vidyapeeth, Vadodara, India*Corresponding author email: [email protected] to cite this article: Annie Jain, Gunvanti Rathod. Oncocytoma of parotid gland: A rare casereport. IAIM, 2015; 2(4): 166-169.Available online at www.iaimjournal.comReceived on: 06-03-2015 Accepted on: 26-03-2015AbstractOncocytomas are benign salivary gland tumors composed of oncocytes, cuboidal to columnarepithelial cells with abundant eosinophilic cytoplasm secondary to the accumulation of excessivenumber of mitochondria. In 1894, the German pathologist Hurthle first described these granularcells in normal canine thyroid glands, while the term \"Oncocyte\" was coined by Hamperl in 1931.Fine Needle Aspiration Cytology (FNAC) has increasingly been used as a primary screening tool forsalivary gland lesions with high levels of sensitivity and specificity. However, caution should beexercised when interpreting aspirates with predominant oncocytic population. Final diagnosis isassisted by CT and/or magnetic resonance imaging (MRI) of the neck and histopathologicexamination.Key wordsFine needle aspiration cytology, Oncocytomas, salivary gland tumors.Introduction sixth decade [2]. The clinical presentation is similar to other benign salivary gland tumors,Oncocytic neoplasms encompass a group of rare that of a slow growing, non tender firmtumors of the parotid glands, and their submandibular mass. Fine needle aspirationincidence represents approximately 1% of (FNA) smears of oncocytic neoplasms revealparotid neoplasms [1]. Oncocytomas are benign cohesive clusters of cells more often in papillarysalivary gland tumors composed of oncocytes, fragments with granular cytoplasm. Here, wecuboidal to columnar epithelial cells with have presented case of 74 years old maleabundant eosinophilic cytoplasm secondary to patient with left parotid oncocytoma.the accumulation of excessive number ofmitochondria. Majority of cases favored an olderpopulation for this rarity, most often after theInternational Archives of Integrated Medicine, Vol. 2, Issue 4, April, 2015. Page 166Copy right © 2015, IAIM, All Rights Reserved.

Oncocytoma of parotid gland ISSN: 2394-0026 (P) ISSN: 2394-0034 (O)Case report normal canine thyroid glands, while the term \"Oncocyte\" was coined by Hamperl in 1931 [10].A 70 years old male presented with a gradually Photo – 1: Moderate cellularity smears ofincreasing painless swelling in the oncocytic cells. (H & E Stain, 10X)region for the past 1 year. It had an insidiousonset and was progressive in nature with no Photo – 2: Cohesive clusters of oncocytes. (H &history of associated pain. The swelling did not E Stain, 40X)resolve following a course of antibiotics. Physicalexamination revealed a 3X3.5 cm firm non- Photo – 3: Oncocytes with granular, eosinophilictender mass in the parotid region which was cytoplasm. (H & E Stain, 60X)mobile and the overlying skin was unaffected.There was no lymphadenopathy noted.Computed tomography (CT) of the parotidglands, neck and thorax revealed a mass in theleft parotid gland (maximum diameter 3.7 cm).The patient was referred to the PathologyDepartment for fine needle aspiration cytology(FNAC), which was performed using a 22-guageneedle attached to a 10 ml syringe [3, 4, 5, 6].Blood mixed particulate material was obtained,air dried and 95% ethanol fixed smears weremade [7, 8, 9] and stained with Giemsa,Haematoxylin and Eosin and Papanicolaoutechniques, respectively. On cytologicalexamination, the smears showed moderatecellularity which composed of epithelial cellclusters. The individual cells consisted of anexclusive population of oncocytic cells seen insheets and papillary clusters along withabundant single cells. (Photo - 1, Photo - 2,Photo – 3) There was also presence of moderateto abundant densely stained granular cytoplasmwith round nuclei and nucleoli. A cytologicaldiagnosis of Oncocytoma of parotid gland wasmade.DiscussionOncocytes are epithelial cells having abundant,granular, eosinophilic cytoplasm, a centralpyknotic nucleus. Ultrastructurally, they arecrammed with numerous mitochondria ofvarious sizes. In 1894, the German pathologistHurthle first described these granular cells inInternational Archives of Integrated Medicine, Vol. 2, Issue 4, April, 2015. Page 167Copy right © 2015, IAIM, All Rights Reserved.

Oncocytoma of parotid gland ISSN: 2394-0026 (P) ISSN: 2394-0034 (O)Oncocytes can be seen in various tissues and a clusters with an attempt at acinus formation,variety of conditions ranging from hyper plastic [13, 14] little or no lymphoid cells, single cellschanges to malignant conditions. Various organs are seen in greater abundance. WT on the othershow presence of oncocytes like salivary glands, hand shows epithelial cells mostly oncocytic, inthyroid, parathyroid, pituitary, nasal cavities, sheets with occasional papillary fragments,sinuses, ocular caruncle, lacrimal glands, buccal single cells are scarce and variable amount ofmucosa, eustachian tube, larynx, esophagus and lymphoid component is present [14].organs like liver, pancreas, and kidney [10, 11]. Differentiating oncocytoma from oncocyticOncocytomas of salivary glands most commonly carcinoma can be difficult on cytology as theinvolve the parotid gland (82%) and the rest are former can appear cytologically malignantlocated at the submandibular gland and minor looking, while the later can look deceptivelysalivary glands. They are typically tumors of monomorphic for which the term \"oncocyticolder adults with a peak incidence at the 8th neoplasm\" is preferred on cytology smears.decade. In our case also the patient was having Differentiating oncocytosis from oncocytoma onage of 74 years. cytology is difficult, and on some occasions, even impossible [15].Fine needle aspiration cytology (FNAC) hasincreasingly been used as a primary screening The accuracy rate for the diagnosis oftool for salivary gland lesions with high levels of oncocytoma on FNAC material is high aboutsensitivity and specificity. However, as salivary 92%, however caution should be taken whenglands are notorious for having overlapping interpreting aspirates with predominantmorphological features, diagnosis by cytology oncocytic population. Benign and reactivealone often becomes difficult [10]. The situation oncocytes show prominent, eosinophilic nucleolican improve by using multiple passes from the along with pleomorphism and this should not beswelling. mistaken for malignancy. Fine needle aspiration is the procedure of choice for making a diagnosisOncocytes may be seen in a variety of non in the majority of cases. Rarity of the disease,neoplastic and neoplastic conditions, ranging sampling error, and lack of interpreterfrom normal glands of elderly individuals to experience are account for majority of pitfalls.tumors such as papillary cystadenoma Diagnosis is assisted by CT and/or magneticlymphomatosum (Wharthin’s tumor-WT) resonance imaging (MRI) of the neck, althoughoncocytoma and oncocytic carcinoma [12]. Cells histopathologic confirmation is necessary.with oncocytic features may also be seen intumors such as pleomorphic adenoma, Conclusionmucoepidermoid carcinoma and rarely aciniccell tumors, salivary duct carcinoma and the The diagnosis of oncocytomas can be madeuncommon oncocytic papillary cystadenoma without any difficulties. However, a diagnostic[12]. challenge can arise when extensive oncocytic metaplasia occurs in other salivary glandThe main differential diagnosis of oncocytoma is tumors. Awareness of the fine microscopicWT specifically when aspiration with details of these lesions coupled to the utilizationpredominant oncocytes in WT. In oncocytoma, of ancillary procedures may avoid misdiagnosis.the epithelial cells are in sheets and papillaryInternational Archives of Integrated Medicine, Vol. 2, Issue 4, April, 2015. Page 168Copy right © 2015, IAIM, All Rights Reserved.

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