Hyalinizing clear cell carcinoma: case series and comprehensive review of the literature

Abstract

Background: Hyalinizing clear cell carcinoma (HCCC) is an uncommon malignant salivary gland tumor that was characterized only recently as a distinct entity. Because of its histologic similarity to several other primary and metastatic tumors and its purported favorable clinical outcome after local resection, it is important to recognize the features of this unusual tumor.

Methods: The authors present 8 new, fully characterized cases of HCCC and systematically reviewed 44 other cases of HCCC reported in the English language literature from 1980 to 2008. Historic cases were reviewed, and available data regarding morphology, special stains, demographics, clinical presentation, radiographic findings, management, and outcomes were extracted. Data from the current series were compared with the earlier published literature.

Results: To the best of the authors' knowledge, this was the largest reviewed series of HCCC and included a total of 52 cases. The findings, which included key histologic features, clinical presentation, and outcome, generally were consistent with what was reported previously. However, the current review revealed that 25% of patients reported in the literature had metastatases at initial presentation, including 10 of 44 patients who had metastases to regional lymph nodes and 1 patient who had metastasis to the lung. The authors were unable to identify any specific histologic features that would predict this behavior.

Conclusions: The current results indicated that HCCC is less indolent than was believed previously; therefore, regional lymph node dissection should be considered in conjunction with wide local excision for patients with HCC.

FIGURE 1

(a) Anastomosing trabeculae and nests of clear cells among hyalinized stroma (hematoxylin and eosin [H&E] stain, original magnification ×100). (b) Nests and cords of a bipopulation with clear cells (arrowhead) and eosinophilic cells (arrow) (H&E stain, original magnification ×200). (c) Strongly positive periodic acid–Schiff (PAS) stain without diastase highlighting the abundant cytoplasmic glycogen (original magnification ×200). (d) Negative PAS stain with diastase digestion (original magnification ×200).