Neuroendocrine adenoma of the middle ear.Neuroendocrine adenomas of the middle ear, also known as middle ear adenomas and carcinoids, are rare neoplasms. These tumors occur equally in the genders, and they usually affect middle-aged patients. Patients present clinically with hearing loss and pain; tinnitus, equilibrium changes, and nerve paralysis might also be identified. Tumors are usually smaller than 1 cm in their greatest dimension, and they occasionally extend into the external or internal auditory canal. Microscopically, neuroendocrine adenomas of the middle ear are unencapsulated and "pseudoinvasive" with moderate cellularity (figure 1). They display several growth characteristics: glandular spaces, trabeculae, festoons, ribbonlike patterns, anastomosing cords, and solid sheets with variable cohesiveness. The glandular spaces frequently contain an amorphous secretory product. The predominant architectural pattern tends to vary among tumors and even within a single tumor. The cells are cuboidal-to-columnar and uniform in size, and they feature eosinophilic eosinophilic /eo·sin·o·phil·ic/ (-fil´ik) 1. readily stainable with eosin. 2. pertaining to eosinophils. 3. pertaining to or characterized by eosinophilia. , finely granular, and homogenous cytoplasm. Cytoplasmic borders are indistinct. The nuclei are round-to-oval with finely dispersed "salt-and-pepper" chromatin, and they may be centrally or eccentrically placed with only minimal pleomorphism pleomorphism /pleo·mor·phism/ (-mor´fizm) the occurrence of various distinct forms by a single organism or within a species.pleomor´phicpleomor´phous ple·o·mor·phism n. 1. . A plasmacytoid appearance may be noted (figure 2). Nucleoli nucleoli plural form of nucleolus. are inconspicuous, and mitoses are essentially absent. The gland-duct spaces are lined with a dual-cell population made up of an inner (luminal), flattened, and slightly more intensely eosinophilic cell surrounded by a basally positioned cuboidal-to-columnar cell. The tumor cells are immunoreactive immunoreactive exhibiting immunoreactivity. with cytokeratin, CK7, and CAM 5.2; CK7 specifically highlights the inner (luminal) layer of the glandular cells. Neuroendocrine marker immunoreactivity includes chromogranin, neuron-specific enolase, human pancreatic polypeptide, synaptophysin, and serotonin. [FIGURES 1-2 OMITTED] All tumors are managed by surgery (simple or modified mastoidectomy Mastoidectomy Definition Mastoidectomy is a surgical procedure to remove an infected portion of the bone behind the ear when medical treatment is not effective. This surgery is rarely needed today because of the widespread use of antibiotics. ); radical mastoidectomy is reserved for tumors that encase the ossicles Ossicles The three small bones of the middle ear: the malleus (hammer), the incus (anvil) and the stapes (stirrup). These bones help carry sound from the eardrum to the inner ear. Mentioned in: Otitis Media, Stapedectomy . Recurrences or re-growths occur in as many as 20% of cases. Removal of the ossicular os·si·cle n. A small bone, especially one of the three bones of the middle ear. [Latin ossiculum, diminutive of os, bone; see ost- in Indo-European roots. chain is usually associated with a reduction in recurrence. Suggested reading Mills SE, Fechner RE. Middle ear adenoma. A cytologically uniform neoplasm neoplasm or tumor, tissue composed of cells that grow in an abnormal way. Normal tissue is growth-limited, i.e., cell reproduction is equal to cell death. displaying a variety of architectural patterns. Am J Surg Pathol 1984;8:677-85. Torske KR, Thompson LD. Adenoma versus carcinoid tumor of the middle ear: A study of 48 cases and a review of the literature. Mod Pathol 2002;15:543-55. Lester D.R. Thompson, MD From the Department of Pathology, Woodland Hills Medical Center, Southern California Permanente Medical Group, Woodland Hills, Calif. |
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