The document describes a Muskett scoring system used to evaluate lymphoid depletion in bursa samples on a scale of 0-5, where 0 indicates no abnormalities and higher numbers indicate increasing severity of lymphoid depletion. Examples are provided of bursa samples assigned scores of 1-5 based on histological features such as degree of lymphoid follicle depletion, infiltration of other cell types, and changes to bursa architecture.

1. Bursa Lesion Score

2. Bursa Lesion Score
Lymphoid depletion recorded using the Muskett score:
0: no histological abnormalities
1: minor lymphoid depletion
2: moderate lymphoid depletion
3: lymphoid depletion
4: severe lymphoid depletion
5: very severe lymphoid depletion

3. 0: no histological abnormalities
1: minor lymphoid depletion
2: moderate lymphoid depletion
3: lymphoid depletion
4: severe lymphoid depletion
5: very severe lymphoid depletion

4. 0: no histological abnormalities
1: minor lymphoid depletion
2: moderate lymphoid depletion
3: lymphoid depletion
4: severe lymphoid depletion
5: very severe lymphoid depletion
• The bursa histologically revealed scattered lymphoid necrosis in a few follicles.
• The cortex and medulla were indistinct.
• There was mild increase in interfollicular stromal tissue.

5. 0: no histological abnormalities
1: minor lymphoid depletion
2: moderate lymphoid depletion
3: lymphoid depletion
4: severe lymphoid depletion
5: very severe lymphoid depletion
• The bursal plica revealed moderate to severe lymphoid depletion in most of the bursal
follicles.
• The lining epithelium was corrugated.

6. 0: no histological abnormalities
1: minor lymphoid depletion
2: moderate lymphoid depletion
3: lymphoid depletion
4: severe lymphoid depletion
5: very severe lymphoid depletion
The bursa revealed severe lymphoid depletion in almost all the follicles, which appeared
pale and vacuolated.
There was infiltration of heterophils in the bursal follicle and inter-follicular stroma.
The lining epithelium was denuded in a few plicae.
In a few follicles there were cellular debris and cystic cavities. The lining epithelium was
corrugated.

7. 0: no histological abnormalities
1: minor lymphoid depletion
2: moderate lymphoid depletion
3: lymphoid depletion
4: severe lymphoid depletion
5: very severe lymphoid depletion
The bursa revealed loss of lymphoid follicles glandular transformation and increase in
inter follicular connective tissue.
Cystic cavities were observed in some follicles.
Infiltration of macrophages, plasma cells and lymphoid cells were observed in the
connective tissue stroma.
The lining epithelium was corrugated.

8. 0: no histological abnormalities
1: minor lymphoid depletion
2: moderate lymphoid depletion
3: lymphoid depletion
4: severe lymphoid depletion
5: very severe lymphoid depletion
Bursa microscopically revealed complete loss of architecture.
There was no intact lymphoid follicle and the entire area was filled up by fibrous tissue.
The lining epithelium was highly corrugated.