Renal oncocytoma misdiagnosed as renal cell carcinoma: report of two cases and literature review / 中国基层医药

Objective:To investigate the clinical, imaging, and pathological characteristics of renal oncocytoma, and to improve the understanding, diagnosis, and treatment of renal oncocytoma.Methods:The imaging and pathological data of two patients misdiagnosed with renal cell carcinoma in the 970 Hospital of PLA Joint Logistics Support Force from January to March 2021 were retrospectively analyzed. The relevant literature was reviewed and discussed.Results:The tumors were located in the left kidney of two patients, with diameters of 2.7 cm and 3.2 cm respectively. The patients underwent retroperitoneal laparoscopic removal of partial left kidney and retroperitoneal laparoscopic removal of the whole left kidney separately. The pathological results confirmed the diagnosis of renal oncocytoma.Conclusion:Renal oncocytoma is a rare benign renal cell tumor which is difficult to be diagnosed before surgery. Contrast-enhanced CT can provide evidence for the identification of renal oncocytoma. Its final diagnosis depends on pathological results.

Crisis hipercalcémica, presentación inusual de adenoma paratiroideo: reporte de 2 casos / Hypercalcemic crisis, unusual presentation of parathyroid adenoma

La crisis hipercalcémica (CH) es una emergencia endocrina inusual, definida por la presencia de calcemia > 14 mg/dl asociada a disfunción renal, alteraciones cardiovasculares, gastrointestinales y del sensorio; también podría considerarse en pacientes con síntomas graves y calcemia menor. El hiperparatiroidismo primario (HPTP) y las neoplasias malignas son las etiologías más comunes de la hipercalcemia (90% de los casos); sin embargo, rara vez el primero se presenta como CH. Debido a la alta mortalidad asociada a esta entidad, es de gran importancia establecer diagnóstico y tratamiento precoces. Presentamos dos pacientes con crisis hipercalcémica como primera manifestación del HPTP, el 1.° con bloqueo auriculoventricular (AV) completo y el 2.° con pancreatitis aguda. La anatomía patológica (AP) reveló adenoma oxifílico en ambos casos, que es una variante histológica poco frecuente y puede manifestarse clínicamente de forma grave. Conclusiones: los adenomas paratiroideos son causa poco frecuente de CH. Consideramos el tipo histológico observado (adenoma oxifílico) como probable factor condicionante. La pancreatitis y especialmente el bloqueo AV son manifestaciones poco frecuentes de la CH. Resaltamos la importancia de la determinación de los niveles de calcio dentro de la evaluación inicial de todo paciente con bloqueo AV. (AU)

Hypercalcemic crisis (HC) is an unusual endocrine emergency, defined as the presence of serum calcium > 14 mg/dl related to kidney dysfunction, cardiovascular, gastrointestinal and sensory disturbances. It could also be considered in patients with severe symptoms and lower serum calcium levels. Primary hyperparathyroidism (PHPT) and malignant neoplasms are the most common hypercalcemia etiologies (90% of cases), nevertheless, the former hardly ever occurs as HC. Due to the high mortality associated with HC, it is crucial to establish early diagnosis and treatment.We report two patients with HC as the first manifestation of PHPT; the former with atrioventricular (AV) block and the latter with acute pancreatitis. Pathology revealed oxyphilic adenoma in both cases, which is an infrequent histological variant that can have a severe clinical manifestation. Conclusions: parathyroid adenomas are a rare cause of HC. We consider the histological type observed (oxyphilic adenoma) as a probable conditioning factor. Pancreatitis and especially AV block are rare manifestations of HC. We emphasize the importance of determining calcium levels in the initial evaluation of all patients with AV block. (AU)

Oncocitoma em carúncula: relato de caso / Oncocytoma of the caruncle: a case report

RESUMO O oncocitoma é um tipo de neoplasia rara na prática clínica e descrito na literatura, principalmente quando localizado no olho. Quando localizado nos anexos oculares, é mais frequentemente na carúncula. Analisou-se o caso de uma paciente de 74 anos, caucasiana, que relatou desconforto visual no olho esquerdo, e cujo exame físico mostrou lesão tumoral na carúncula esquerda, com volume moderado, presença de neovascularização e secreção excessiva. A excisão cirúrgica da lesão foi realizada sob sedação, e a peça foi enviada para avaliação anatomopatológica. A lesão foi diagnosticada histologicamente como oncocitoma, sem malignidade, e a paciente não apresentou recidiva após o procedimento. Embora raro, esse tumor deve ser reconhecido pelos oftalmologistas, devido ao risco já relatado de desenvolvimento de adenocarcinoma.

ABSTRACT Oncocytoma is a neoplasm rarely observed in clinical practice and reported in the literature, especially when located in the eye. When described in the ocular adnexa, it is most often located in the caruncle. The case of a 74-year-old Caucasian female patient is reported. She complained of visual discomfort in the left eye, and physical examination showed a tumoral lesion in the left caruncle, of moderate volume, presence of neovascularization, and excessive secretion. Surgical excision of the lesion was performed under sedation, and the specimen was sent for pathological examination. The lesion was histologically diagnosed as oncocytoma with no malignancy, and the patient presented no recurrence after the procedure. Although rare, this tumor must be recognized by ophthalmologists due to the risk of developing adenocarcinoma, as already reported.

Renal oncocytoma in a kidney transplant patient: the imaging features on contrast-enhanced ultrasonography (CEUS): a case report / Oncocitoma renal em paciente transplantado: achados de imagem na ultrassonografia com contraste

Abstract Renal oncocytoma is an infrequently reported renal neoplasm, often asymptomatic, which usually behaves as a benign entity and is identified accidentally on radiological imaging. Transplant patients under long-term immunosuppressive drugs have a high prevalence of cancers, such as skin cancers, lymphoproliferative disorders, and renal carcinomas. We present a case report of an asymptomatic renal oncocytoma in a kidney transplant recipient presenting persistent hematuria. The features of computed tomography and contrast-enhanced ultrasound (CEUS) are presented. This was the first time we used CEUS in a transplant kidney recipient presenting a renal mass, allowing the real-time visualization of contrast-enhancement patterns during all vascular phases for the differential diagnosis of renal tumors. Although the pattern of intense vascularization could mislead to an early judgment as a malignant lesion, it could help to exclude other renal lesions without inducing nephrotoxicity.

Resumo O oncocitoma renal é uma neoplasia renal raramente relatada, muitas vezes assintomática, que geralmente se comporta como uma entidade benigna e é identificada acidentalmente em imagens radiológicas. Pacientes transplantados em regimes imunossupressores de longa duração apresentam alta prevalência de neoplasias tais como câncer de pele, distúrbios linfoproliferativos e carcinomas renais. Apresentamos o relato de um caso de oncocitoma renal assintomático em receptor de transplante renal com hematúria persistente. São apresentados os achados de imagens de tomografia computadorizada e ultrassonografia (US) com contraste. Foi a primeira vez que utilizamos a US com contraste em um receptor de transplante renal que apresentava massa renal, permitindo a visualização em tempo real dos padrões de realce do contraste em todas as fases vasculares para o diagnóstico diferencial dos tumores renais. Embora o padrão de vascularização intensa possa induzir uma avaliação precoce de lesão maligna, o exame ajuda a excluir outras lesões renais sem induzir nefrotoxicidade.

Oncocytoma of the lacrimal gland: a case report / Oncocitoma de glândula lacrimal: relato de caso

ABSTRACT Here we describe a rare case of a benign tumor in the lacrimal gland of a healthy 4-year-old girl. Mild proptosis was the only abnormality observed on clinical examination. Magnetic resonance imaging of the right orbit revealed an oval, solid, well-circumscribed, homogeneous mass extending from the lacrimal gland and measuring 2.5 × 2.3 × 1.7 cm without any evidence of invasion into adjacent bones. The lesion was surgically excised and histological analyses defined the diagnosis of oncocytoma of the lacrimal gland. Although rare, oncocytoma should be included in the differential diagnosis of lacrimal gland tumors.

Resumo Nós descrevemos um raro caso de tumor benigno na glândula lacrimal em uma criança sadia de 4 anos de idade. Clinicamente, a paciente apresentava apenas uma discreta proptose. A ressonância nuclear magnética (RNM) de órbita direita revelou a presença de uma massa oval, sólida, bem-circunscrita, homogênea, se extendendo a partir da glândula lacrimal, medindo 2,5 cm x 2,3 cm x 1,7 cm, sem nenhum sinal evidente de invasão a estrutura óssea adjacente. A lesão foi cirurgicamente removida e analizada histopatologicamente, sendo estabelecido o diagnóstico de oncocitoma de glândula lacrimal. Apesar de raro, o oncocitoma deve ser incluído no diagnóstico diferencial de qualquer tumor originado da glândula lacrimal.

Oncocitoma: caso clínico / Oncocytoma: a clinical case

El oncocitoma es un tumor benigno que afecta varios órganos como tiroides, paratiroides, riñón y glándulas salivales, que consiste en la proliferación de células oncocíticas producidas por una gran hiperplasia mitocondrial. El oncocitoma representa menos del 1 por ciento de todos lostumores de las gandulas salivales. Cuando en estudios por imágenes de glándula parótida se observen múltiples pequeños nódulos con unamasa sólida o quística, el diagnóstico de oncocitoma debe ser considerado, especialmente en pacientes de sesenta o más años. El objetivo de este artículo es la presentación de un caso de oncocitoma y analizar el estado de arte de los casos reportados en la temática.

The oncocytoma is a benign neoplastic tumor that occurs in several organs, including the thyroid gland, parathyroid gland, kidneys, and salivary glands consisting of a proliferation of oncocytic cells produced by a large mitochondrial hyperplasia. The oncocytoma accounts for less than 1% of the whole salivary gland tumors.When multiple small nodules are found in the parotid gland with a large solid or cystic mass that is evident on imaging, a diagnosis of oncocytoma should be considered, particularly in patients of sixty years of age or older. The objective of this article is the presentation of a case of oncocytoma and the state of art of reported cases in this field.

Adenocarcinoma oncocítico oxifílico de endometrio: reporte de caso / Endometrial oncocytic carcinoma: a case report

El cáncer de endometrio es la patología maligna más frecuente del tracto genital femenino, con una incidencia del 3,2 por ciento en Latinoamérica, y que según sus características histológicas permite clasificar las lesiones en tipo I o II. Entre las variantes de esta última se encuentra el adenocarcinoma oxifílico. Se presenta caso de una paciente de 77 años con cuadro de hemorragia uterina anormal y dolor pélvico crónico, que posterior a estudios complementarios es llevada a histerectomía ampliada, en su estudio histopatológico final se encuentra lesión compuesta por células epiteliales con abundante citoplasma intensamente acidofílico con núcleos pleomórficos e hipercromáticos dispuestos en un patrón arquitectural de predominio sólido, positivo para CK7, CK14 y parcialmente positivo para Bcl2, diagnosticándose adenocarcinoma oxifílico de endometrio. Este caso resulta importante debido al poco número de reportes a nivel mundial y por ser el primero encontrado en Colombia.

Endometrial cancer is the most frequent malignant pathology of the female genital tract, with an incidence of 3.2 percent in Latin America. Histological characteristics lead to classify this lesions in type I or II where oxyphilic adenocarcinoma is included as a variant of the last group. This is a case report of a 77 years old patient with clinical symptoms of abnormal uterine bleeding and chronic pelvic pain thatafter complementary studies is carried to extended hysterectomy; further histopathological study showed a lesion formed by epithelial cells with abundant intensely acidophilic cytoplasm with pleomorphic and hyperchromatic nuclei arranged in a predominantly solid architectural pattern, positive for CK14, CK7 and partially positive for Bcl2, diagnosing endometrial oxyphilic adenocarcinoma. This case is remarkable important because of the small number of reports worldwide and being the first found in Colombia.

Nasolacrimal Duct Obstruction Caused by Oncocytic Carcinoma

Here, we report an extremely rare case of acquired nasolacrimal duct obstruction caused by oncocytic carcinoma. A 64-year-old man presented to the hospital complaining of epiphora and left-side nasal obstruction. Ophthalmic and otolaryngology examination revealed a left lacrimal duct obstruction caused by a mass in the left nasal cavity and lacrimal drainage system. The mass was removed and confirmed as an oncocytic carcinoma. Nine months after surgery, without adjuvant radiotherapy, a left orbital mass was observed and the patient underwent reoperation. The mass proved to be recurrent oncocytic carcinoma. The patient underwent adjuvant radiotherapy to eradicate any residual tumor and the patient remains tumor-free one year post-radiotherapy.

Nasolacrimal Duct Obstruction Caused by Oncocytic Carcinoma

Here, we report an extremely rare case of acquired nasolacrimal duct obstruction caused by oncocytic carcinoma. A 64-year-old man presented to the hospital complaining of epiphora and left-side nasal obstruction. Ophthalmic and otolaryngology examination revealed a left lacrimal duct obstruction caused by a mass in the left nasal cavity and lacrimal drainage system. The mass was removed and confirmed as an oncocytic carcinoma. Nine months after surgery, without adjuvant radiotherapy, a left orbital mass was observed and the patient underwent reoperation. The mass proved to be recurrent oncocytic carcinoma. The patient underwent adjuvant radiotherapy to eradicate any residual tumor and the patient remains tumor-free one year post-radiotherapy.

Differential Diagnosis of Chromophobic Renal Cell Carcinoma and Renal Oncocytoma:Dynamic Contrast-Enhanced CT Analysis / 中国医学影像学杂志

Purpose To explore the diagnostic value of dynamic contrast-enhanced CT (DCE-CT) in the differential diagnosis of chromophobic renal cell carcinoma (CRCC) and renal oncocytoma (RO). Materials and Methods A retrospective study was carried out on the DCE-CT findings of 24 patients with pathologically-proved CRCCs and 17 patients with pathologically-confirmed ROs. The enhancement percentage (EP) and the enhancement index (EI) of both types of lesions were compared on corticomedullary phase and nephrographic phase. Results CRCCs on corticomedullary phase and nephrographic phase:EP (132.8±39.8)%and (99.2±32.5)%, respectively;EI 0.31±0.11 and 0.30±0.12, respectively. ROs on corticomedullary phase and nephrographic phase:EP (234.1±129.1)%and (195.4±87.1)%, respectively;EI 0.66±0.33 and 0.68±0.28, respectively. Both EP and EI of CRCCs and ROs showed statistical difference (P<0.05). As the threshold value of EI on nephrograhic phase was 0.44, the sensitivity was 82.4%, specificity was 91.7% and Youden index was 0.74. Conclusion Imaging features of DCE-CT, especially EI on nephrographic phase, are helpful in the differential diagnosis of CRCC and RO.

Carcinoma e oncocitoma em mesmo rim- relato de caso / Carcinoma and oncocytoma in the same kidney- case report

Oncocitoma e carcinoma de células renais representam2 a 3% dos tumores no adulto. O oncocitoma é benigno,do córtex renal, normalmente unilateral, sendo 3,1-6,6%de todas as neoplasias renais. Os carcinomas são tumoresde células epiteliais, malignos, com tendência à invasãotecidual, podendo originar metástases. Os carcinomas representam85% dos cânceres renais, sendo prevalente o decélulas claras. No relato de caso os autores evidenciam,através do estudo histopatológico, a presença de oncocitomae carcinoma de células claras em um único rim.

Oncocytoma and renal cell carcinoma correspond to 2-3% of all tumors in adults. Oncocytomas are benign, usuallyin the kidney cortex and unilateral, correspondingto 3,1 to 6,6 % of all renal neoplasm. Carcinomas aremalignant tumors of epithelial cells which tend to tissueinvasion and can result in metastasis. Carcinoma represents85% of kidney neoplasm, with the clear cell carcinomabeing the most prevalent type. In the case reportthe authors demonstrate, through the histopathologicalstudies, the presence of oncocytoma and clear-cell carcinomain the same kidney.

Oxyphilic Adenoma Involving Floor of The Mouth : A Case Report.

Oxyphilic adenomas are unusual neoplasm of the head and neck region affecting the glandular epithelial tissue. They were first called as oncocytoma, which is composed of oncocytes and were first described by Schaffer and Hamperl. Oncocytes are polyhedral cells and contain abundant cytoplasm filled with eosinophilic granules. Oxyphilic adenomas are benign neoplasm and represent approximately less than 1% of all salivary gland tumors. They are found generally in the parotid gland, affecting parotid gland region extraorally and rarely encountered in various other sites. Involvement of floor of the mouth is very rare. Presented in this article is a case report of patient suffering from neoplasm, which was histopathologically diagnosed as oxyphilic adenoma.

Diagnostic Utility of Caveolin-1 and MOC-31 in Distinguishing Chromophobe Renal Cell Carcinoma from Renal Oncocytoma

PURPOSE: Renal tumors consist of heterogeneous groups that frequently show complex and overlapping morphology, thus making it difficult to make a correct diagnosis. One of the most problematic differential diagnoses is to distinguish chromophobe renal cell carcinoma (RCC) from oncocytoma. These should be distinguished by differences in their behavior and clinical outcome. Our study was performed to identify whether caveolin-1 and MOC-31 are useful immunohistochemical markers for differentiating chromophobe RCC from oncocytoma. MATERIALS AND METHODS: We selected 23 chromophobe RCCs, 8 oncocytomas, and 25 clear cell RCCs and performed immunohistochemical staining for caveolin-1 and MOC-31. RESULTS: Caveolin-1 was positive in 20 (87%) of 23 chromophobe RCCs, 0 of 8 oncocytomas, and 21 (84%) of 25 clear cell RCCs. MOC-31 was positive in 22 (96%) of 23 chromophobe RCCs, 2 (25%) of 8 oncocytomas, and 14 (56%) of 25 clear cell RCCs. There was a statistically significant difference in the expression of caveolin-1 and MOC-31 between chromophobe RCC and oncocytoma (p<0.001). In addition, clear cell RCC was also significantly different from oncocytoma in the expression of caveolin-1 (p<0.001) and was significantly different from chromophobe RCC in the expression of MOC-31 (p<0.001). CONCLUSIONS: Caveolin-1 and MOC-31 can be useful markers in the differential diagnosis of chromophobe RCC, oncocytoma, and clear cell RCC.

Virilizing Adrenocortical Oncocytoma in a Child: A Case Report

Functioning adrenocortical oncocytomas are extremely rare and most reported patients are 40-60 yr of age. To our knowledge, only 2 cases of functioning adrenocortical oncocytomas have been reported in childhood. We report a case of functioning adrenocortical oncocytoma in a 14-yr-old female child presenting with virilization. She presented with deepening of the voice and excessive hair growth, and elevation of plasma testosterone and dehydroepiandrosterone sulfate. She had an adrenalectomy. The completely resected tumor composed predominantly of oncocytes without atypical mitosis and necrosis. A discussion of this case and a review of the literature on this entity are presented.

Oncocytoma and Oncocytic Carcinoma of the Salivary Glands, Single Institute Experience

BACKGROUND: Oncocytic neoplasms of the salivary glands are rare and the differential diagnosis between oncocytic carcinomas (OCs) and oncocytomas is difficult. We present 5 cases of oncocytoma and 3 cases of OC of the salivary glands with clinicopathological and immunohistochemical comparisons. METHODS: Eight cases of oncocytic neoplasms diagnosed at Asan Medical Center between 1998 and 2009 were reviewed for clinical data and histological features. Immunohistochemical staining for epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (Her-2), c-kit, p53, and Ki-67 was done. RESULTS: Cytological differences between oncocytomas and OCs were not obvious, but unequivocal infiltrative growths were identified in 3 cases, rendering the diagnosis of oncocytic carcinoma. When the remaining cases were classified as oncocytomas, there was no difference in age, size, and clinical symptoms between oncocytomas and OCs. Two of 3 OCs showed strong membranous expression of c-kit, but all oncocytomas were negative. The proportion of p53-positive cells was larger in OCs than oncocytomas. Her-2 or EGFR expression was absent, and Ki-67 labeling indices were less than 1% in all cases. CONCLUSIONS: An infiltrative growth pattern, strong membranous expression of c-kit, and an increased proportion of p53-positive cells are features that can differentiate OCs from oncocytomas of the salivary glands.

A Functioning Adrenocortical Oncocytoma

Adrenocortical oncocytomas are exceptionally rare and most are benign and nonfunctioning. Only 3 cases of adrenal oncocytomas have been reported in the Korean literature and all of them were nonfunctioning. Herein, we report a case of a functioning adrenocortical oncocytoma in a 49-year-old man who presented with Cushing syndrome.

Fatores preditores de malignidade em neoplasias de células de Hurthle / Predictor factors of malignancy in Hürthle cell neoplasms

OBJETIVO: neoplasias de células de Hurthle são tumores da glândula tireóide de baixa incidência que apresentam muitas controvérsias quanto à distinção entre carcinomas e adenomas. O objetivo deste estudo foi identificar fatores preditores de malignidade neste tipo específico de neoplasia. MÉTODOS: entre janeiro de 1999 e junho de 2006, 56 casos de neoplasia de células de Hurthle foram diagnosticados em nossa instituição e foram estudados retrospectivamente. RESULTADOS: trinta e sete pacientes apresentaram diagnóstico patológico de adenoma de células de Hurthle (ACH), enquanto 19 casos foram diagnosticados como carcinoma de células de Hurthle (CCH). No grupo de pacientes com adenomas a idade média foi de 47,8 anos, sendo que trinta e cinco (94 por cento) eram do sexo feminino e apenas dois (5,5 por cento) casos do sexo masculino. O tamanho médio dos adenomas foi de 2,1 cm variando de 0,3 a 6,0 cm. Entre os 19 casos de carcinomas a média de idade foi de 51,1 anos, sendo quatorze casos em mulheres (73 por cento) e cinco em homens (26,4 por cento). O tamanho médio dos nódulos neste grupo foi de 3,8 cm, variando de 2,0 cm a 7,5 cm. CONCLUSÃO: Pacientes com neoplasias de células de Hurthle apresentando nódulos maiores que três centímetros, principalmente em homens, apresentam maior risco de malignidade.

BACKGROUND: Hürthle cell neoplasms are uncommon thyroid gland tumors that present a diagnostic challenge due to difficulties to differentiate between adenomas and carcinomas. The purpose of this study is to identify preoperative predictor factors of malignancy. METHODS: A retrospective study of patients and tumor characteristics of 56 Hürthle cell tumors cases diagnosed in our institution between January 1999 and June 2006 was done. RESULTS: Thirty-seven patients presented with adenoma, 35 women (94.5 percent) and 2 men (4.5 percent) with average age of 47.8 years. Medium tumor size in this group was 2.1 cm (ranging from 0.3 to 6.0 cm). Nineteen patients with Hürthle cell carcinoma were found in this series with 14 (73 percent) female and 5 male patients with average age of 51.1 years. Tumor size in this group ranged between 2.0 and 7.5 cm (medium of 3.8 cm). CONCLUSION: Patients with Hürthle cell neoplasm nodules larger than 3.0 cm, in the greatest diameter, especially in male patients, are predictor factors of having malignancy.

Adrenocortical Oncocytoma / 대한비뇨기과학회지

An adrenocortical oncocytoma is very rare and unusual disease. Only 22 and 2 cases have been reported in the foreign and Korean literatures, respectively. Herein, the case of a left adrenocortical oncocytoma, observed by ultrasonography during a periodic medical examination of a 32 year old male patient is reported.

Reassessment of the Usefulness of 18F-FDG PET in the Evaluation of Adrenal Masses Detected on CT or MR

PURPOSE: To reassess the usefulness of 18F-FDG PET in the differential diagnosis of benign and malignant tumors from adrenal masses detected on CT or MR. MATERIALS AND METHODS: A retrospective analysis was performed on 20 patients (n = 21), on whom PET scans were obtained with characteristically benign CT (n = 21) and MR (n = 2) findings. Seventeen patients had a proven primary malignancy and three patients had adrenal incidentalomas. PET findings were interpreted as positive if the 18F-FDG uptake of the adrenal mass was greater than or equal to that of the liver. Each adrenal mass was characterized by its size and standardized uptake value (SUV). For statistical analysis, the t-test was used to analyze results for size and SUV. RESULTS: PET findings were positive for eight adrenal masses; two masses were pathologically proven as adrenocortical oncocytomas. The false positive rate was 38% in all patients and 41% in patients with a malignancy. CONCLUSION: 18F-FDG PET was useful in evaluating the primary lesions as well as metastases, but a high false positive rate in patients with a primary malignancy should be considered in the diagnosis of metastasis to the adrenal gland.

Oncocytic Glomus Tumor: A Case Report

Oncocytic glomus tumor is a newly recognized, rare variant of glomus tumor. In this study, we describe a case of oncocytic glomus tumor occurring in the nail bed of the finger. A 25-year-old woman presented with a tiny and painful mass on her hand, and she had had this lesion for six years. Upon microscopic examination, there were oval to polygonal tumor cells characterized by plump eosinophilic granular cytoplasm, which were arranged in sheets around the thin vessels. Immunohistochemically, the tumor cells were strongly reactive for smooth muscle actin, vimentin, and negative for S-100 protein, alpha-fetoprotein, HMB-45, desmin, CD34, and pancytokeratin. The diagnosis was a glomus tumor of the oncocytic variant.