Dedifferentiated Chondrosarcoma of the Larynx

Abstract

Primary dedifferentiated chondrosarcoma occurring in the larynx is a rare head and neck malignancy. The cases reported in the literature suggest male gender predilection and variable clinical outcomes ranging from disease-free survival to disease-related death. Although a calcified matrix is suggestive of chondrosarcoma, the dedifferentiated component is not readily appreciated on conventional imaging modalities and thorough tissue sampling is necessary for confirming the diagnosis. Histologically, there is an abrupt transition from a well-differentiated chondrosarcoma to a high-grade spindle cell component, which can show focal heterologous differentiation. These features are exemplified in this sine qua non radiology-pathology correlation article.

Keywords: Cricoid cartilage; Head and neck malignancy; Heterologous differentiation; Larynx; Primary dedifferentiated chondrosarcoma; Well-differentiated chondrosarcoma.

Fig. 1

Axial (a) and coronal (b) contrast-enhanced CT images demonstrate a mass arising from the anterior cricoid cartilage (arrows) with a calcified matrix. There is associated airway narrowing extension of the tumor into the strap muscles

Fig. 2

Cut surface of surgical resection specimen a is variably white-tan and glistening with focal central degenerative change. Low power histologic view b shows normal cricoid cartilage (black arrow) surrounded by conventional chondrosarcoma and dedifferentiated chondrosarcoma (white arrow). Both grade 1 (c, bottom left) and grade 2 (c, top right) conventional chondrosarcoma are present. Undifferentiated spindle cell sarcoma areas d with mitotic figures (arrow) confirm dedifferentiated chondrosarcoma. High-grade malignant cells surrounded by osteoid e with mitotic figures (arrow) suggest heterologous osteosarcomatous differentiation