Respiratory System Pathology for 3rd Year Medical Students PDF

College of Medicine & Health Sciences Histopathology Department Respiratory system-pathology For 3rd year Medical student  Objectives At the end of this lecture you must be able to: Describe the risk factors, morphology, and clinical features of Nasopharyngeal....

College of Medicine & Health Sciences Histopathology Department Respiratory system-pathology For 3rd year Medical student  Objectives At the end of this lecture you must be able to: Describe the risk factors, morphology, and clinical features of Nasopharyngeal. Describe the risk factors, morphology, clinical features and staging of Laryngeal tumors.  Tumors of the Nose, Sinuses, and Nasopharynx Tumors in these locations are infrequent but include the entire category of mesenchymal and epithelial neoplasms. Brief mention is made of somewhat distinctive types. Nasopharyngeal Angiofibroma. This is a highly vascular tumor that occurs almost exclusively in adolescent males. Despite its benign nature, it may cause serious clinical problems because of its tendency to bleed profusely during surgery.  Sinonasal Papillomas. - Benign neoplasms arising from the sinonasal mucosa - Composed of squamous or columnar epithelium. - HPV (types 6 and 11) have been identified in the lesions. Occur in three forms: 1- Septal (most common). 2- Inverted (most important biologically). 3- Cylindrical.  Inverted papillomas - Benign but locally aggressive neoplasms - Occurring in both the nose and the paranasal sinuses. - Papillomatous proliferation of squamous epithelium. - High rate of recurrence. - Potentially serious complication of invasion of The masses of squamous epithelium are growing inward; hence, the term inverted. the orbit or cranial vault. - Frank carcinoma may also develop(rarely).  Nasopharyngeal Carcinomas Characterized by : - Distinctive geographic distribution, - Close anatomic relationship to lymphoid tissue. - An association with EBV infection.  Nasopharyngeal Carcinomas Takes one of three patterns: (1) keratinizing squamous cell carcinomas. (2) Nonkeratinizing squamous cell carcinomas. (3) Undifferentiated carcinomas Three sets of influences apparently affect the origins of these neoplasms: (1) Heredity. (2) Age. (3) Infection with EBV.  Nasopharyngeal carcinomas Tend to grow silently until they have become unresectable and have often spread to cervical nodes or distant sites. - Radiotherapy is the standard modality of treatment. - About a 50% to 70% 3-year survival rate. - The undifferentiated carcinoma is the most radiosensitive and the keratinizing the least radiosensitive.  Morphology On histologic examination: The keratinizing and nonkeratinizing squamous cell lesions more or less resemble usual well- differentiated and poorly differentiated squamous cell carcinomas arising in other locations. The undifferentiated variant is composed of large epithelial cells with oval or round vesicular nuclei, prominent nucleoli, and indistinct cell borders disposed in a syncytium-like array. Admixed with the epithelial cells are abundant, mature, normal-appearing lymphocytes. lymphoepithelioma type. The syncytium-like nests of epithelium are surrounded by lymphocytes.  CARCINOMA OF THE LARYNX Sequence of Hyperplasia-Dysplasia-Carcinoma. Hyperplasia, atypical hyperplasia, dysplasia, carcinoma in situ, and invasive carcinoma. Macroscopically: the epithelial changes range from smooth, white or reddened focal thickenings, sometimes roughened by keratosis, to irregular verrucous or ulcerated, white-pink lesions looking like cancer.  Risk factors The various changes described are most often related to: -Tobacco smoke, the risk being proportional to the level of exposure. Indeed, up to the point of frank cancer, the changes often regress after cessation of smoking. -However, alcohol is also clearly a risk factor and other factors may contribute to increased risk, - Including nutritional factors, exposure to asbestos, and irradiation. -HPV sequences are present in about 5% of cases.  Manifestation Carcinoma of the larynx manifests itself clinically by persistent hoarseness.  Morphology About 95% of laryngeal carcinomas are typical squamous cell tumors. Rarely, adenocarcinomas are seen, presumably arising from mucous glands. The tumor usually develops directly on the vocal cords, but it may arise above or below the cords. Those confined within the larynx proper are termed intrinsic, whereas those that arise or extend outside the larynx are called extrinsic. Squamous cell carcinomas of the larynx follow the growth pattern of all squamous cell carcinomas.  Laryngeal carcinoma Note the large, ulcerated, fungating lesion involving the vocal cord and piriform sinus. B, Histologic appearance of laryngeal squamous cell carcinoma. Note the atypical lining epithelium and invasive keratinizing cancer cells in the submucosa.  SQUAMOUS PAPILLOMA AND PAPILLOMATOSIS Laryngeal squamous papillomas are benign neoplasms, usually on the true vocal cords, that form soft, raspberry-like excrescences rarely more than 1 cm in diameter. On histologic examination, the papillomas are made up of multiple slender, finger-like projections supported by central fibrovascular cores and covered by an orderly, typical, stratified squamous epithelium. When the papillomas are on the free edge of the vocal cord, trauma may lead to ulceration that Diagrammatic comparison of a benign papilloma and an exophytic carcinoma of the larynx to can be accompanied by hemoptysis. highlight their quite different appearances.  Papillomas -Usually single in adults but are often multiple in children, in whom they are referred to as juvenile laryngeal papillomatosis. -However, multiple recurring papillomas also occur in adults. -The lesions are caused by HPV types 6 and 11. They do not become malignant, but they frequently recur. -They often spontaneously regress at puberty, but some affected patients endure numerous surgeries before this occurs. -Cancerous transformation is rare. See you in the next lecture