Head and Neck Pathology

Secretory carcinoma (SC) is a recently described salivary gland carcinoma with characteristic ETV6-NTRK3 fusion. In this case report, we described a SC of the maxillary sinus that underwent high grade transformation in a 61-year-old patient. The diagnosis was confirmed by the presence of ETV6 translocation. Within the sinonasal tract, SC is an important differential diagnosis especially of sinonasal adenocarcinoma, non-intestinal type (non-ITAC), as these two entities bears histologic and immunophenotypic similarity. Distinction between these two tumors can be challenging based on the morphology alone and may require additional immunohistochemical and molecular studies. It is important to recognize that SC can occur in the sinonasal tract as correctly diagnosing SC may be prognostic relevant and may provide new targeted therapeutic avenues for these patients.

The spectrum of “developmental” lesions that occur in the head and neck predominantly congenital in origin and arising at birth and/or discovered in childhood is broad and fascinating. These have been grouped into categories such as “ectopias”, “heterotopias”, “hamartomas”, and “choristomas”. On a philosophical and consequently systematic level, these lesions, mostly benign tumors seem to lack a true understanding of the pathogenetic foundation on which to base a more unified taxonomic designation. In this review, we will consider some of these select tumors as they represent syndromic associations (nasal chondromesenchymal hamartoma and DICER1 syndrome), the lingual choristoma from the perspective of its nomenclature and classification, lesions with ectopic meningothelial elements, and teratomas and the enigmatic “hairy polyp” in reference to a broader discussion of pathogenesis and pluripotent cells in the head and neck. A consistent thread will be how these lesions are designated with some final thoughts on future directions regarding the investigation of their pathogenesis and taxonomic nomenclature.

The 2017 fourth edition of the World Health Organization Classification of Tumours, specifically as it relates to the ear (Chap. 9), has several changes. Importantly, the number of entities has been significantly reduced by omitting tumors or lesions if they do not occur exclusively or predominantly at this site or if they are discussed in detail elsewhere in the book. These entities include: embryonal rhabdomyosarcoma, osteoma, exostosis, angiolymphoid hyperplasia with eosinophilia, Schneiderian papilloma, inverted papilloma, lipoma of the internal auditory canal, hemangioma, hematolymphoid tumors, and secondary tumors. Paraganglioma was included in the neck chapter. New entries include otosclerosis and cholesteatoma, while refinements to nomenclature, classification and criteria were incorporated into the ceruminous gland tumors and epithelial tumors of the middle and inner ear. Specifically, the middle and inner ear were combined, as practical limitations of origin and imaging make a definitive separation artificial. The classification reflects the state of current understanding for these uncommon entities, with this update only highlighting selected entities that were the most significantly changed.

We present the case of an uncommon example of a plexiform fibrohistiocytic tumor (PFHT) occurring in the anterior central neck region of a 40 year-old female with previous subtotal thyroidectomy. The tumor clinically mimics a complicated thyroglossal duct cyst. On fine needle aspiration cytology, the tumor was composed of sheets of bland spindle cells and nests of plump histiocytoid cells in vaguely whorled arrangements. Occasional multinucleated giant cells were also identified. The excised specimen showed an irregular, highly infiltrative subcutaneous tumor arranged in a nodular/plexiform pattern concentrated to the center of the tumor mass. In addition, the tumor contained numerous tongue-like extensions composed of variably cellular, fibroblastic/fibromatosis-like areas. These fibroblastic/fibromatosis-like extensions reached far from the epicenter of the tumor and were associated with scattered small plexiform nodules of histiocytic cells. These tongue-like extensions multifocally involved the surgical margins. The fibroblastic and histiocytoid cells showed diffuse smooth muscle actin (SMA) expression. The multinucleated giant cells and also the histiocytoid proliferation were positive for CD68. This case illustrates an uncommon both anatomical and demographic manifestation of PFHT and also characterize the fine needle aspiration cytologic features in this tumor, which previously have been reported in a few cases.

To evaluate the performance characteristics of PD-L1 immunohistochemistry (IHC) combined positive scoring (CPS) in core biopsies and aspirate cell blocks from patients with head and neck squamous cell carcinoma (HNSqCCa). PD-L1 IHC using the SP263 antibody was performed on 20 paired cases which consisted of a small biopsy and an excisional specimen. The scores were compared at both the 1% and 20% cutpoints. Using the CPS result obtained from the resected specimen or excisional biopsy as the gold standard, PD-L1 IHC performed on the core biopsy or cell block identified 4 of 6 positive cases (66%) at the 20% cutpoint and 12 of 17 (70%) positive patients at the 1% cutpoint. False positive cases were uncommon at both cutpoints. CPS scoring should be used with caution in small biopsies from patients with HNSqCCa. A negative result should prompt consideration of an excisional biopsy and repeat testing.