Journal of Cytology
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Year : 2012  |  Volume : 29  |  Issue : 1  |  Page : 60-62
Granular cell tumor in inguinal region: A case of mistaken identity on cytology

1 Department of Pathology, Sri Ramachandra University, Porur, Chennai, India
2 Professor of Pathology, Sri Ramachandra University, Porur, Chennai, India
3 Professor of Surgery, Sri Ramachandra University, Porur, Chennai, India
4 Professor of Radiology, Sri Ramachandra University, Porur, Chennai, India

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Date of Web Publication27-Feb-2012


A 63-year-old male presented with sudden increase in size of a right inguinal swelling which was present for the past 10 years. Clinical diagnosis of inguinal soft tissue mass/lymph node enlargement was made and patient was investigated further for a conclusive diagnosis. Ultrasound examination suggested it to be a lymph node and guided fine needle aspiration cytology was performed. Cytology was suggestive of a reactive lymph node. Subsequently, an excision biopsy was performed that revealed a granular cell tumor with many lymphoid aggregates. On reviewing the cytosmears, we realised that the granular neoplastic cells were mistaken for histiocytes; and the lymphoid background and bare nuclei mislead us to consider it a reactive lymph node. Since granular cell tumor can occur almost anywhere, a careful examination of cytosmears and knowledge of its distinctive cyto-morphological features would be helpful in providing an accurate diagnosis on cytology.

Keywords: Granular cell tumor; histiocytes; inguinal; lymphocytes

How to cite this article:
Rao S, Rajendiran S, Surendran P, Venkata Sai P M, Prathiba D. Granular cell tumor in inguinal region: A case of mistaken identity on cytology. J Cytol 2012;29:60-2

How to cite this URL:
Rao S, Rajendiran S, Surendran P, Venkata Sai P M, Prathiba D. Granular cell tumor in inguinal region: A case of mistaken identity on cytology. J Cytol [serial online] 2012 [cited 2020 Jun 6];29:60-2. Available from:

   Introduction Top

Granular cell tumors (GCT) are uncommon soft tissue neoplasms that may be asymptomatic or may present as a slow growing nodule. It is usually diagnosed based on its characteristic cytological and histomorphological features. We present a case of granular cell tumor in the right inguinal region misdiagnosed as a reactive lymph node on cytology.

   Case Report Top

A 63-year-old male presented with swelling in the right inguinal region for the past 10 years with a sudden increase in size since two months. On examination, a single, firm three cm swelling was felt in the right inguinal region. No abnormality was detected in the left inguinal region. No other lesion such as an ulcer or swelling was noted in the right leg or thigh.

There was no history of fever, rigors and loss of weight or appetite in the recent past. Patient gave no history of exposure to tuberculosis.

On general examination, patient was well built and nourished. There was no pallor or generalized lymphadenopathy. No abnormality was detected on systemic examination. Base line blood investigations were found to be within normal limits. An ultrasonogram of the right inguinal mass showed circumscribed hypoechoic mass suggestive of a lymph node shadow. An ultrasound guided aspiration was done and the smears were submitted for cytological examination. Ultrasonogram of the abdomen was unremarkable.

Cytosmears examined were moderately cellular with dual cell population, composed predominantly of oval to polygonal cells with abundant cytoplasm and round bland nuclei resembling histiocytes [Figure 1]. These cells were arranged in loose clusters and as isolated forms. The background showed few discrete round cells with round nuclei and scanty cytoplasm suggestive of mature lymphocytes [Figure 1]. No precursor lymphoid cells were seen on cytosmears. In correlation with clinical and image findings, an impression of reactive lymph node was suggested on cytology. A clinical follow-up and excision was advised if clinically suspicious or lesion further increased in size.
Figure 1: (a) Moderately cellular cytosmear showing clusters of cells with histioid appearance, lymphoid cells and few bare nuclei (MGG, ×100); (b) Cytological smear with loose clusters of oval to polygonal cells having basophilic granular cytoplasm (MGG, ×200)

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An excision biopsy was performed which showed skin with a neoplasm located in lower dermis and subcutis. Tumor cells were arranged in nests with focal diffuse pattern. Individual cells appeared round to oval with abundant granular eosinophilic cytoplasm and centrally placed bland nuclei [Figure 2]. Focal collections of lymphocytes were also seen [Figure 2]. Tumor cells were seen surrounding the adnexal structures and nerve fibres. Immunohistochemistry showed S100 positivity in nucleus and cytoplasm ([Figure 2] inset). Immunostains for CD68 and inhibin showed cytoplasmic positivity. A final diagnosis of granular cell tumor was given based on histology and immunoprofiling.
Figure 2: Section show diffusely arranged tumor cells with granular eosinophilic cytoplasm intervening adnexal structures and presence of lymphoid aggregate (H and E, ×100); Inset show tumor cells showing cytoplasmic and nuclear immunopositivity for S100 protein (IHC, ×100)

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   Discussion Top

Granular cell tumor is a rare benign tumor arising predominantly in skin, subcutaneous tissues and tongue. [1] They may occur at any age, but commonly affects third to fourth decades of life. Generally, these are isolated lesions, but can be multiple in about 15% of cases. [2] Usually, these tumors behave in a benign fashion, but malignant variant can also occur de novo or from transformation of a benign one. Earlier GCT was proposed to be derived from immature skeletal muscle cells (hence, the term granular cell myoblastoma was given). However, later ultrastructure and immunohistochemistry studies have proven it to be of schwannian differentiation. [1],[3]

Granular cell tumors show non-specific features on MRI and may only be useful in assessing precise location of tumors which is essential for preoperative evaluation. In our case study, only an ultrasonogram was done.

In general, cytological smears of GCT show moderate to high cellularity with uniform appearing large cells arranged in syncitium and as isolated cells. These cells have small round uniform bland nuclei and abundant dense granular cytoplasm. [4]

Cytoplasmic granules are positive for periodic acid Schiff stain and resistant to diastase. Rarely, intranuclear inclusion has also been reported. Lymphoid infiltrate and stripped nuclei resembling lymphocytes may also be seen. [5] The granularity in cytoplasm of tumor cells is due to accumulation of secondary lysosomes resulting in its typical appearance on microscopy and thus deriving its name.

In our case, due to the presence of lymphoid cells, the lesion was mistaken for a lymph node and the granular cells were incorrectly identified as histiocytes on cytology. Since it was a long-standing inguinal swelling with mild increase in size for the last two months, a possibility of reactive lymph node was favored. On reviewing the cytosmears, the larger cells appearing as histiocytes were definitely very granular and this is not a feature of sinus histiocytes. Absence of precursor forms of lymphoid cells was another noticeable feature on cytosmears. Misdiagnosis, in our case, was due to several reasons, foremost being the site of occurrence, clinical and radiological opinion of enlarged lymph node and finally misinterpretation of cytosmears.

Vikas et al[5] in a case study observed lymphoid aggregates in cytosmears of GCT.Cytological smears in our case showed mature lymphocytes and histopathology of the excised tissue showed features of granular cell tumor with many lymphoid aggregates. This finding suggests that lymphocytes can sometimes feature in cytological smears of GCT and can confuse the pathologist. Another feature on cytology that can further confound is the occurrence of stripped nuclei from tumor cells of GCT resembling nucleus of lymphocyte. Granular cell tumor can rarely occur within a lymph node and it is important to know this fact to avoid a mistaken diagnosis of a metastatic tumor. [5]

Cell block is a useful technique that provides additional information from cytological specimen as it displays microhistology which can be further utilized for immunohistochemical studies. In the present case, possibly preparation of cell block would have revealed the right diagnosis. Our case further emphasizes that cell blocks should be considered in image guided aspiration as the material obtained in such cases is through a specialized invasive technique and a repeat aspiration would be cumbersome task.

We present this case to create awareness among the cytologists regarding the difficulties encountered in the cytodiagnosis of granular cell tumor. The possibility of granular cell tumor should be considered when viewing single and cluster of large cells with abundant eosinophilic granular cytoplasm and vesicular nuclei on cytology.

   References Top

1.Pathania K, Bhargava S. Granular cell tumour of breast: A mimic of carcinoma. MJAFI 2010;66:292-4.  Back to cited text no. 1
2.Lack EE, Worsham GF, Callihan MD, Crawford BE, Klappenbach S, Rowden G, et al. Granular cell tumor: a clinicopathologic study of 110 patients. J Surg Oncol 1980;13:301-16.  Back to cited text no. 2
3.Ordonez NG. Granular cell tumor: a review and update. Adv Anatomic Pathol 1999;6:186-203.  Back to cited text no. 3
4.Liu K, Madden JF, Olatidove BA, Dodd LG. Features of benign granular cell tumor on fine needle aspiration. Acta Cytol 1999;43:552-7.  Back to cited text no. 4
5.Vikas SK, Vyankatesh TA. Fine needle aspiration cytology of a subcutaneous granular cell tumor. Bangladesh J Pathol 2010;25:23-4.  Back to cited text no. 5

Correspondence Address:
Shalinee Rao
Assoc Professor of Pathology, Department of Pathology, Sri Ramachandra University, Porur, Chennai - 116
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0970-9371.93229

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This article has been cited by
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[Pubmed] | [DOI]


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