Respiratory Tract and Mediastinum

Abstract

Intermediate squamous cells are characterized by round to oval monomorphic nuclei with smooth membrane and fine loose chromatin. They have a low N/C ratio. The cytoplasm is transparent and cyanophilic. z { Superficial squames have small pyknotic nuclei and broad orangeophilic cytoplasm. Columnar CellsCiliated columnar cells exfoliate most frequently from the tracheobronchial tree, less frequently from the upper respiratory tract (nasal cavity, sinuses, larynx). Nonciliated cuboidal to columnar cells mainly originate from the bronchioles. Ciliated columnar cells are constantly present in exfoliative respiratory samples. They occur numerously in specimens of induced sputum, in postbronchoscopy sputum, in bronchial aspirates and brushings. They are uncommon in BAL and FNAB specimens.z { The bronchial epithelial cell is characterized by a columnar shape, which at one end tapers off to terminate in a tail-like process. At the opposite or luminal end of the cell, there is a flat terminal plate, anchoring the cilia. The nucleus is located toward the cytoplasmic tail exhibiting a round to oval shape, smooth outline, conspicuous membrane, loose chromatin, and one or multiple small nucleoli. PeculiarCellular Response to Irradiation and Chemotherapy (Figs. 2.13 and 2.72) Reactive cell changes induced by irradiation and chemotherapy can be easily recognized by experienced microscopists. Microscopic Features z { The atypical cells are markedly enlarged, many of them show multinucleation. z { The N/C ratio is preserved; cytoplasmic vacuoles are numerous and prominent. z { The nuclei are pleomorphic; they frequently show indentations and grooves. Occasional nuclear vacuolization. z { The chromatin texture is characterized by fine and coarse granules; and chromatin strands outlining nuclear areas give the nucleus a peculiar empty look. z { Macronucleoli. CautionCarcinoma cells and benign epithelial cells showing strong degenerative changes induced by ionizing radiation are difficult to distinguish from each other .