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Year : 2023  |  Volume : 66  |  Issue : 3  |  Page : 664-666
Leiomyoma of the palatine tonsil - report of a rare and unusual tumor at this site

1 Department of Histopathology, The Rotherham NHS Foundation Trust, UK
2 Department of Pathology, Subharti Medical College, Meerut, Uttar Pradesh, India
3 Department of Histopathology, Max Super Speciality Hospital, New Delhi, India

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Date of Submission11-Jul-2021
Date of Acceptance09-Aug-2021
Date of Web Publication12-May-2022


A leiomyoma is a remarkably rare cause of a benign, one-side tonsillar enlargement. The diagnosis is essentially histologic and will not normally be suspected clinically. Immunohistochemistry is needed for substantiation of the morphology and confirmation. We submit this illustrative case report.

Keywords: Leiomyoma, lump, smooth muscle, tonsil, unilateral

How to cite this article:
Abrari A, Tyagi A, Mukherjee U. Leiomyoma of the palatine tonsil - report of a rare and unusual tumor at this site. Indian J Pathol Microbiol 2023;66:664-6

How to cite this URL:
Abrari A, Tyagi A, Mukherjee U. Leiomyoma of the palatine tonsil - report of a rare and unusual tumor at this site. Indian J Pathol Microbiol [serial online] 2023 [cited 2023 Sep 30];66:664-6. Available from:

   Introduction Top

A unilaterally enlarged tonsil may be a consequence of infection, inflammation, or neoplasm. While lymphoma and squamous cell carcinoma is the preeminent malignancy of tonsil, one-sided benign tonsillar enlargements usually have multifarious causes, including squamous papilloma, lymphangioma, epidermal inclusion cyst, juvenile angiofibroma, hemangioma, fibroepithelial polyp, fibroma, fibroxanthoma, lipoma, adenoma, and chondroma.[1],[2]

An isolated benign smooth muscle tumor (leiomyoma) is very uncommon in the head and neck and oral cavity and its occurrence in the tonsil counts as a distinct rarity. Given the scarcity of this lesion in this region and the uniqueness of this diagnosis, we are putting forth this case of a leiomyoma of the palatine tonsil.

   Case Report Top

A female patient aged 40 years presented in the ENT OPD with complaints of relapsing and remitting sore throat for 6 months, of late, increasing in frequency and compounded by an agonizing pain in the throat, worsening on swallowing.

The clinical examination revealed a globular 2.5 cm × 1.5 cm × 1.0 cm smooth-surfaced mass, bulging from the right palatine tonsil. The computed tomography of the oropharynx and neck showed an enhancing mass in the right tonsillar region. The right tonsillar bed, peri-tonsillar tissues, and left tonsil were reported as unremarkable. This patient underwent a right tonsillectomy under general anesthesia.

The operative surgical notes described a firm, rounded right tonsillar mass, with intact overlying mucosa? lymphoma.

Grossly, a solid, firm to hard tonsillar mass of 2.5 cm × 1.5 cm × 1.5 cm was received. The cut surface was tan gray and striated. No necrosis was noted. No definite gross impression beyond neoplastic was formed macroscopically.

With the clinical suspicion of lymphoma and no inkling of an unusual lesion, the opportunity for capturing a gross image was not secured.

Histologically, there was a sub-mucosal, circumscribed, non-encapsulated lesion consisting of interlacing fascicles of monotonous spindle cells with indistinct borders, eosinophilic cytoplasm, and cigar-shaped nuclei. Some thick-walled vessels were interspersed. There was no significant cytological atypia, mitotic activity, or coagulative necrosis [Figure 1]. This was a quintessential spindle cell tumor with rather bland leiomyomatoid cells. The vascular wall origin of the lesional cells was diligently searched for and not detected in the present case.
Figure 1: 1: H and E X10, lesional spindle cells below the tonsillar surface epithelium seen as a band at the upper border of the section. 2: H and E X20, lesional cells with an interspersed blood vessel. Note lack of any necrosis. 3, 4: H and E X40, lesional spindle cells showing distinctly leiomyomatoid cells in the intersecting fascicles. Note absence of cellular atypia, mitoses, or necrosis

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Immunohistochemistry showed the lesional cells to be positive for smooth muscle actin, h-caldesmon, and desmin with a proliferation index of <1% [Figure 2]. The remaining immunomarkers, namely CD34, CD31, S-100, Myogenin, TLE-1, HMB45, Melan-A, CD117, AE1-AE3, Cam 5.2, EMA, CK5-6, p63, and TLE1 were not expressed. This immunomorphology was interpreted as compatible with a tumor with smooth muscle phenotype—lacking malignant attributes and a histologic diagnosis of leiomyoma was rendered.
Figure 2: Immunohistochemistry: lesional cells express Actin (1), h-Caldesmon (2), and Desmin (3). Ki67 marked nuclei are few, <1% (4)

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There was no history or clinical features suggesting preceding or concomitant leiomyomas at the other sites. There were no significant associated clinical conditions or pathologies in this patient.

   Discussion Top

The fact that that these lesions are so rare at this location, compounded with their non-specific clinical presentation, ensures that this diagnosis will usually not be suspected until the histology is available.

For the wary histopathologist, even with the morphology evoking a smooth muscle phenotype, it is prudent that he/she runs the full gamut of immunomarkers targeted at a spindle cell tumor, to forestall any diagnostic slip-up. Thus, the pathologic workup of the present case, in addition to the smooth muscle markers (actin, desmin, and h-caldesmon) included vascular (CD31, CD34), epithelial/myoepithelial (AE1-AE3, EMA, Cam 5.2, CK5-6, p63), rhabdomyogenic (myogenin), melanocytic/perivascular epithelioid cell (S-100, HMB45, Melan-A), synovial sarcoma defining (TLE1), and GIST related (CD117). All these latter markers were found to be not expressed by the lesional cells. The ER was not included in the first instance in the comprehensive immunohistochemistry panel employed for assessing the tonsillar spindle cell lesion in this case.

Leiomyomata in the human body frequently occur, where native smooth muscle is structurally present, and thus, these not surprisingly are common in the genito-urinary and gastro-intestinal tracts and skin.[3] The head and neck region hosts less than 1% of the human leiomyomata overall and the tonsillar location of these is vanishingly rare.[4] The lack of significant smooth muscle depots in the oral cavity likely accounts for the paucity of oral/tonsillar leiomyomas, although a fair series of 14 oral angioleiomyomas is available.[5] On the other hand, a conscientious search of the literature yielded a single tonsillar leiomyoma[6] and an angioleiomyoma.[7] To this paltry listing, we wish to add the present case.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Jones A. Tumours of the hypopharynx and esophagus. In: Gleeson M, et al., editors. Scott-Brown's Otorhinolaryngology, Head and Neck Surgery. Great Britain: Hodder Arnold Publishers; 2008. p. 2635.  Back to cited text no. 1
Schwartz LH, Ozsahin M, Zhang GN, Touboul E, De Vataire F, Andolenko P, et al. Synchronous and metachronous head and neck carcinomas. Cancer 1994;74:1933-8.  Back to cited text no. 2
Weiss SW, Goldblum JR. Benign tumors of smooth muscle. In: Weiss SW, Goldblum JR, editors. Enzinger and Weiss's Soft Tissue Tumors. 5th ed. Philadelphia: Mosby; 2008.  Back to cited text no. 3
Gianluca S, Marini R, Tonoli F, Cristalli MP. Leiomyoma of oral cavity: Case report and literature review. Ann Stomatol (Roma) 2011;2:9-12.  Back to cited text no. 4
Aitken-Saavedra J, da Silva KD, Gomes AP, Vasconcelos AC, Etges A, Nóbrega TG, et al. Clinicopathologic and immunohistochemical characterization of 14 cases of angioleiomyomas in oral cavity. Med Oral Patol Oral Cir Bucal 2018;23:e564-8.  Back to cited text no. 5
Greenberg E, Shupak A, Kelner J, Meyer WS. Tonsillar leiomyoma. J Laryngol Otol 1987;101:619-23.  Back to cited text no. 6
Shetty SC, Kini U, D'Cruz MN, Hasan S. Angioleiomyoma in the tonsil: An uncommon tumour in a rare site. Br J Oral Maxillofac Surg 2002;40:169-71.  Back to cited text no. 7

Correspondence Address:
Aarti Tyagi
Department of Pathology, Subharti Medical College, Meerut, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijpm.ijpm_708_21

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