Benign and Reactive Changes

Benign and Reactive Changes
Michael J. Thrall, MD
Key Facts
Clinical Issues
  • Reactive cytologic changes often appear in setting of pneumonia
  • Radiation and chemotherapy changes should be kept in mind
  • Localized changes create diagnostic dilemmas because radiologic patterns for injury and malignancy often overlap
Cytopathology
  • Alveolar macrophages and bronchial epithelium are readily sampled, resulting in highly cellular specimens
  • Reactive cells may be numerous and predominant or may only be a small subpopulation
  • Reactive changes often appear in setting of altered background with inflammation or debris
  • Architectural distortion, nuclear enlargement, increased pleomorphism, multinucleation, and prominent nucleoli are typical of reactive processes
  • Reactive cells typically have pale nuclei with less chromatin clumping than malignant cells
  • Cilia and terminal bars are indicators of benign changes
  • Reserve cell hyperplasia is characterized by very small cohesive cells
  • Creola bodies can be recognized as benign by analysis of relatively well-visualized cells at the edge, which may have cilia
Top Differential Diagnoses
  • Adenocarcinoma
  • Squamous cell carcinoma
The reactive changes seen on this Pap stain are due to organizing pneumonia and include reassuring pale chromatin and prominent nucleoli yet striking architectural disorder and nuclear pleomorphism.
The radiation changes seen on Pap stain include marked nuclear enlargement and atypia. Prominent multinucleation supports a benign interpretation in this case.
ETIOLOGY/PATHOGENESIS
Reactive Changes
  • May be seen in context of any form of lung injury: Chronic or acute, diffuse or localized
CLINICAL ISSUES
Presentation
  • Reactive cytologic changes often appear in setting of pneumonia sampled primarily to look for organisms
  • Radiation and chemotherapy changes should be kept in mind in specimens from patients with history of malignancy
IMAGE FINDINGS
General Features
  • Localized changes create diagnostic dilemmas because of overlapping radiologic patterns for injury and malignancy
CYTOPATHOLOGY
Cellularity
  • Normal and reactive lung samples are typically highly cellular
    • Lavage easily picks up free intraalveolar macrophages
    • Bronchial cells are copiously shed during brushings and washings
Background
  • Normal lung has clean background
  • Reactive changes often appear in setting of altered background
    • Increased acute inflammation is frequently a feature in samples with reactive change
    • Necrotic debris associated with lung injury may also be seen in setting of reactive changes
Cells
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Jul 6, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Benign and Reactive Changes

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