Radiation changes

Radiation changes
Diagnosis in short
Radiation changes. H&E stain.
LM	cytoplasmic vacuolation (usually abundant), enlarged nuclei - but usu. normal NC ratio, no nuclear membrane irregularies, chromatin "smudgy", +/-multinucleation, +/-fibrosis (chronic change), +/-edema (acute change)
LM DDx	pleomorphic tumours - esp. sarcomas, poorly differentiated carcinomas, drug/toxin effect
IHC	Ki-67 low, pankeratin -ve (usu.)
Site	pretty much anywhere
Clinical history	history of radiation treatment/exposure - important for the diagnosis
Prognosis	benign
Clin. DDx	cancer recurrence, infection, new malignancy, post-surgical changes

Radiation changes, also radiation effect, are seen occasionally by pathologists. They are usually a result of prior (radiation) treatments. The history is important in making this diagnosis

General

• History of radiation treatment/exposure.
• Clinical symptoms dependent on site.

Gross

• +/-Erythema (early)
• +/-Fibrotic appearing tissue (late).

Microscopic

Features:

• Cytoplasmic vacuolation - usually abundant.
• Nucleus:
  • Enlarged nucleus - but normal NC ratio.
  • No nuclear membrane irregularies.
  • Chromatin: "smudgy".
  • +/-Multinucleation.
• +/-Fibrosis (chronic change).
• +/-Edema (acute change).

Important note:

• The atypical cells are stromal cells; these survive the radiation. The epithelium is usually normal in the context of chronic changes.
• Pleomorphism is often suggestive of malignancy. Paradoxically, in the context of radiation, less pleomorphic (clonal-appearing) cells may be malignant!

DDx:

• Pleomorphic tumours.

Images

Rectum

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  Radiation proctitis - low mag. (WC)

• 

  Radiation proctitis - intermed. mag. (WC)

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  Radiation proctitis - high mag. (WC)

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  Radiation proctitis - very high mag. (WC)

• 

  Radiation proctitis - intermed. mag. (WC)

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  Radiation proctitis - high mag. (WC)

• 

  Radiation proctitis - high mag. (WC)

Prostate gland

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  Prostate with RC - low mag.

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  Prostate with RC - intermed. mag.

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  Prostate with RC - high mag.

www:

• Prostate with radiation changes (webpathology.com).
• Prostate with radiation changes (webpathology.com).

IHC

• Pankeratin -ve.
• KI-67 low.

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RECTUM, BIOPSY:
- SQUAMOUS MUCOSA WITH MARKED ACUTE INFLAMMATION AND REACTIVE CHANGES.
- GRANULATION TISSUE.
- LARGE ATYPICAL STROMAL CELLS AND FIBROSIS, COMPATIBLE WITH THE HISTORY
  OF RADIATION TREATMENT.
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.

URINARY BLADDER, TRIGONE, BIOPSY:
- INFLAMED UROTHELIAL MUCOSA WITH SQUAMOUS METAPLASIA, ULCERATION AND 
  GRANULATION TISSUE FORMATION.
- RADIATION CHANGES (STROMA).
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.

Urinary bladder, biopsy:
- Urothelial mucosa with evidence of ulceration (fibrin, 
  necroinflammatory debris), mild stromal atypia and chronic 
  inflammation, compatible with radiation cystitis
- Negative for dysplasia 
- Negative for malignancy

Micro

Scattered rare large atypical cells with a preserved nucleus-to-cytoplasm ratio are present. Fibrosis is present.

See also

• Radiation colitis.
• Radiation changes in cervical cytology.
• Radiation changes of the endocervical epithelium.
• Radiation oncology.
• Endometrium post-ablation.