Hyalinizing clear cell carcinoma explained

Hyalinizing clear cell carcinoma
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Field:	Oncology, ENT surgery

Hyalinizing clear cell carcinoma (HCCC) is a rare malignant salivary gland tumour, with a good prognosis, that is usually found on the tongue or palate.^[1]

Signs and symptoms

HCCCs typically present as a painless mass in the mouth.^[2]

Diagnosis

HCCCs are diagnosed by examination of tissue, e.g. a biopsy.

Pathology

HCCC consist of cells with abundant clear cytoplasm, arranged in cords, trabeculae or clusters in a hyalinized stroma.^[3] Nuclear pleomorphism is usually minimal and mitoses are infrequently seen.^[2]

Owing to their glycogen content, which explains the "clear" appearance under the microscope, tumour cells stain with PAS. Immunostains for S100 and smooth muscle actin (SMA) are typically negative, but positive for cytokeratins and epithelial membrane antigen (EMA).

HCCCs typically have a recurrent chromosomal translocation, t(12;22), involving the genes EWSR1 and ATF1.^[4] The same translocation is seen in clear cell sarcoma.

The histologic differential diagnosis includes mucoepidermoid carcinoma (clear cell variant), acinic cell carcinoma (clear cell variant), epithelial-myoepithelial carcinoma and metastatic clear cell carcinoma.

Prognosis

They generally have a good prognosis.^[5]

Notes and References

1. Kauzman A, Tabet JC, Stiharu TI . Hyalinizing clear cell carcinoma: a case report and review of the literature . Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics . 112 . 1 . e26–e34 . July 2011 . 21669357 . 10.1016/j.tripleo.2011.02.041 .
2. Milchgrub S, Gnepp DR, Vuitch F, Delgado R, Albores-Saavedra J . Hyalinizing clear cell carcinoma of salivary gland . The American Journal of Surgical Pathology . 18 . 1 . 74–82 . January 1994 . 7506496 . 10.1097/00000478-199401000-00007 . 30519518 .
3. O'Sullivan-Mejia ED, Massey HD, Faquin WC, Powers CN . Hyalinizing clear cell carcinoma: report of eight cases and a review of literature . Head and Neck Pathology . 3 . 3 . 179–185 . September 2009 . 20596970 . 2811632 . 10.1007/s12105-009-0124-3 .
4. Antonescu CR, Katabi N, Zhang L, Sung YS, Seethala RR, Jordan RC, Perez-Ordoñez B, Have C, Asa SL, Leong IT, Bradley G, Klieb H, Weinreb I . 6 . EWSR1-ATF1 fusion is a novel and consistent finding in hyalinizing clear-cell carcinoma of salivary gland . Genes, Chromosomes & Cancer . 50 . 7 . 559–570 . July 2011 . 21484932 . 10.1002/gcc.20881 . 20457515 . free .
5. Masilamani S, Rao S, Chirakkal P, Kumar AR . Hyalinizing clear cell carcinoma of the base of tongue: a distinct and rare entity . Indian Journal of Pathology & Microbiology . 54 . 1 . 167–169 . 2011 . 21393908 . 10.4103/0377-4929.77393 . free .