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, well-differentiated tumours in the background of radiation changes, "giant cell cystitis"
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

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Radiation changes, also radiation effects, 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:^[1]

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.
Well-differentiated carcinoma, e.g. postradiation prostatic carcinoma, may go unnoticed in the background of radiation-associated nuclear changes.
Atypia associated with drugs.
"Giant cell cystitis" - benign mesenchymal atypia with or without inflammation.

Images

Rectum

Radiation proctitis - low mag. (WC)
Radiation proctitis - intermed. mag. (WC)
Radiation proctitis - high mag. (WC)
Radiation proctitis - very high mag. (WC)
Radiation proctitis - intermed. mag. (WC)
Radiation proctitis - high mag. (WC)
Radiation proctitis - high mag. (WC)

Prostate gland

Prostate with RC - low mag.
Prostate with RC - intermed. mag.
Prostate with RC - high mag.

Brain

Glioblastoma with RC (WC/jensflorian)
Radiation necrosis (WC/Tdvorak)
Radiation necrosis and gliosis (WC/Tdvorak)

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.

References

↑ Gupta, S.; Mukherjee, K.; Gupta, YN.; Kumar, M. (Aug 1987). "Sequential radiation changes in cytology of vaginal smears in carcinoma of cervix uteri during radiotherapy.". Int J Gynaecol Obstet 25 (4): 303-8. PMID 2887465.

[pmid2887465-1] Gupta, S.; Mukherjee, K.; Gupta, YN.; Kumar, M. (Aug 1987). "Sequential radiation changes in cytology of vaginal smears in carcinoma of cervix uteri during radiotherapy.". Int J Gynaecol Obstet 25 (4): 303-8. PMID 2887465.

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