Carcinoma cuniculatum (CC) is a rare variant of extremely well differentiated squamous cell carcinoma. We present the clinicopathological features of two cases of CC; one lingual and one esophageal case with a molecular genetic study regarding the TP53 gene mutational status. Case 1 was a 62 year old male with enlarging chronic ulcer in the tongue. Case 2 was a 77 year old male with progressive dysphagia and odynophagia. Both patients were treated surgically. Both tumors showed deeply invaginating, keratin-filled, burrowing crypts lined by very well differentiated squamous epithelium. The esophageal tumor showed varying degrees of reactive nuclear atypia largely limited to the areas with dense intratumoral infiltration of neutrophils. No mutation of TP53 was identified in the esophageal case. Cytologic atypia limited to areas of significant acute inflammation may occur in CC and should, in the absence of aggressive stromal invasion, not preclude a diagnosis of CC.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

No abstract

Mucoepidermoid carcinoma (MEC) with a predominant spindle cell composition occurring in the palatine tonsil is exceedingly rare. We present a case of a 17-year-old boy with an uncommon spindle cell variant of MEC arising in the palatine tonsil. Histologically, the tumor showed a solid, noncystic architecture and was composed of a predominant population of bland spindle to fusiform cells arranged in organoid nests with interspersed goblet cells and focal areas of ductular structures. Reverse transcriptase polymerase chain reaction and fluorescence in situ hybridization (FISH) revealed the presence of a t(11;19) CRTC1-MAML2 gene fusion in this rare variant of MEC. This is the first case report of a spindle cell MEC of the palatine tonsil, with molecular genetic confirmation. It illustrates the importance of awareness and recognition of this uncommon histological variant of MEC, which will help establish appropriate treatment and prognostication.