Indian Journal of Pathology and Microbiology

: 2010  |  Volume : 53  |  Issue : 3  |  Page : 582--584

Metastatic synovial sarcoma, masquerading a carcinoma from a tonsillar primary: A rare case presentation

Bharat Rekhi1, Sangeeta B Desai1, Suprita Arya2, Shubda V Kane1, Nirmala A Jambhekar1,  
1 Department of Pathology, Tata Memorial Hospital, Mumbai, India
2 Department of Radiology, Tata Memorial Hospital, Mumbai, India

Correspondence Address:
Bharat Rekhi
Department of Pathology, 8th Floor, Annex Building, Tata Memorial Hospital, Dr E.B. Road, Parel, Mumbai-400 012

How to cite this article:
Rekhi B, Desai SB, Arya S, Kane SV, Jambhekar NA. Metastatic synovial sarcoma, masquerading a carcinoma from a tonsillar primary: A rare case presentation.Indian J Pathol Microbiol 2010;53:582-584

How to cite this URL:
Rekhi B, Desai SB, Arya S, Kane SV, Jambhekar NA. Metastatic synovial sarcoma, masquerading a carcinoma from a tonsillar primary: A rare case presentation. Indian J Pathol Microbiol [serial online] 2010 [cited 2021 Nov 30 ];53:582-584
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Full Text


Synovial sarcoma (SS) is clinicopathologically and genetically, a distinct soft tissue sarcoma, invariably characterized by aggressive behavior, yet amenable to treatment. About 5-10% SSs occur in the head and neck region, including rare mucosal sites, such as a tonsil. [1,2] Herein, we report an uncommon case of a tonsillar SS with cervical nodal metastasis.

A 32-year-old man referred with recurrent bilateral tonsillar enlargements and right-sided neck swelling of 1 year duration. Earlier, he had undergone tonsillectomy on either side, 1 and 2 years back, elsewhere, whose details are not available. Two months ago, he underwent another excision in the right tonsillar area-in the hypopharynx and of a cervical node. On oral examination, bilateral tonsillar enlargement was noted.

On magnetic resonance imaging, bilateral enlarged retropharyngeal nodes, more on the right side, measuring 3.3 x 2.4 cm were noted, along with 1.3-cm hyperintense masses in the left tonsillar area, in the left oropharyngeal wall, in the right lateral nasopharyngeal wall, and along the lateral border and base of the right tongue. In addition, an enlarged hyperintense node was noted at level II along with several smaller nodes at levels IB, II, and III [Figure 1]a, b.

A tonsillar biopsy was performed at our hospital and the sides with paraffin block from the cervical lymph node and earlier tonsillar excision, performed elsewhere, were reviewed with an outside diagnosis of a poorly differentiated papillary adenocarcinoma with lymph node deposits.

The outside tonsillar biopsy comprised grey-white soft tissue bits measuring 0.9 Χ 0.8 Χ 0.4 cm along with a cystic lymph node mass measuring 2.6 Χ 2.3 Χ 1.5 cm.

Whereas the hematoxylin and eosin (H and E)-stained sections from the tonsillar biopsy performed at our hospital showed inflammatory granulation tissue with a small focus of neoplastic spindle cells, the referral microsections revealed an intranodal cystic and solid tumor, exhibiting a biphasic cell pattern, comprising round to oval and spindle-shaped cells arranged in the glands with focal intraglandular mucin, papillae, and hemangiopericytomatous vasculature. Cells revealed vesicular nuclear chromatin and indistinct cytoplasm. Mitoses were inconspicuous. Focal necrosis was identified. Diagnosis of a SS was provisionally offered. Special stains, such as reticulin, highlighted the reticulin fibers around cell groups, as well as around single cells. Periodic acid-Schiff (PAS) with diastase highlighted the eosinophilic secretions [Figure 2]a-f. On immunohistochemistry (IHC), tumor cells were diffusely positive for vimentin, MIC2 (cytoplasmic), and bcl2. Epithelial membrane antigen (EMA) was mostly positive in the areas of glandular differentiation. CK7 and CK19 showed focal positivity. Cytokeratin (CK), CD34, S100 protein, smooth muscle actin (SMA), desmin, MyoD-1, myogenin, and p63 were negative [Figure 3]a-g. Diagnosis of a biphasic SS was ascertained.

Tonsil is an extremely rare site for an SS, where relatively, possibility of a carcinoma is higher. Still rare is a cervical lymph node metastasis from a primary tonsillar SS, as noted in the present case. [1],[2] The epithelial differentiation in this sarcoma is possibly related to its proclivity for nodal metastasis in about 12.5% cases. [1]

Histologically, an SS is either biphasic or monophasic with a variable mesenchymal (spindly) and epithelial (polygonal) cell differentiation. In the present case, the primary tonsillar tissue and cervical node showed an identical tumor with polygonal to spindle-shaped cells. This led to differential diagnoses, including a metastatic adenocarcinoma, a myoepithelial carcinoma, and a salivary gland carcinoma. Clinically, a squamous carcinoma was another differential that was easily ruled out on histomorphology due to glandular and papillary differentiation with intraglandular mucin. Furthermore, lack of intracellular mucin ruled out a mucoepidermoid carcinoma. On IHC, diffuse vimentin positivity, along with EMA, bcl2, and cytoplasmic MIC2 expression, despite CK negativity were helpful. CK7 and CK19 exhibited discrete focal positivity. Lack of CK with retained EMA and CK7, CK19 expression indicates the value of usage of a panel of epithelial antibody markers to assert an epithelial differentiation in a SS. Negative SMA and S100 made the possibility of a "pure" myoepithelial carcinoma, less likely. In addition to S-100 negativity, lack and the aforementioned IHC profile ruled out a malignant peripheral nerve sheath tumor. Desmin negativity ruled out a spindle cell rhabdomyosarcoma. In view of an uncommon location, the case was subjected to polymerase chain reaction technique for t(X; 18) (p11.2; q11.2) SYT-SSX analysis that is noted in more than 90% cases of SS. [3] However, the results turned negative for SYT-SSX1 and SYT-SSX2. The literature describes SYT-SSX4 as another variant transcript from the t(x; 18) and lately, t(X; 20) (p11.2; q13.3) translocation resulting in SSL18L1/SSX in an SS that was unavailable with us. [4] Presence of the latter variants is a possible reason for the negative molecular analysis in our case. Nonetheless, the histomorphology with unequivocal IHC results were confirmatory of the diagnosis. Lately, TLE-1 (transducin-like enhancer of split) has been identified as a useful marker in the diagnosis of an SS. [5] However, this was not performed in our case.

To sum up, an index of suspicion with distinct histopathologic features, coupled with a panel of IHC markers are useful in substantiating a diagnosis of an SS at rare sites, such as a tonsil. Whereas a metastatic carcinoma makes a patient candidate for chemotherapy (CT) regime, diagnosis of a metastatic SS would possibly subject the patient for adjuvant radiotherapy, a differing CT, and surgery.


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