Immune System

Spleen - Congestion

Narrative

Comment:

Congestion of the spleen is characterized by excessive distension of sinuses within the red pulp by erythrocytes (Figure 1 and Figure 2, arrows). Splenic congestion is common, although a cause is not always apparent. Iatrogenic factors affecting the amount of blood within the splenic sinuses in rats and mice include the manner of death, the method of euthanasia, and necropsy procedures. Other causes of splenic congestion include cardiovascular disease, mononuclear cell leukemia in rats, and erythrocyte damage secondary to treatment. Congestion of the spleen should be distinguished from angiectasis, hemorrhage, hemangioma, and hemangiosarcoma. Angiectatic blood vessels in the spleen can be congested, but "splenic congestion" is typically a more generalized lesion involving the red pulp sinuses. Congestion can be difficult to differentiate from hemorrhage in the spleen; however, it is not typically associated with hematomas or neoplasia (see Spleen - Hemorrhage ). Splenic hemangiomas and hemangiosarcomas are neoplasms derived from the splenic vascular endothelium. Congestion of neoplastic vascular channels may occur with splenic hemangiomas and hemangiosarcomas; however, the diagnosis "Spleen - Congestion" should be reserved for congestion of the red pulp sinuses.

Recommendations:

Whenever congestion in the spleen is believed to be associated with treatment or with a gross lesion, it should be diagnosed and assigned a severity grade.

Related Links:

Spleen - Hemorrhage

References:

National Toxicology Program. 2007. NTP TR-535. Toxicology and Carcinogenesis Studies of 4-Methylimidazole (CAS No. 822-36-6) in F344/N Rats and B6C3F1 Mice (Feed Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/13651

National Toxicology Program. 2010. NTP TR-557. Toxicology and Carcinogenesis Studies of β-Myrcene (CAS No. 123-35-3) in F344/N Rats and B6C3F1 Mice (Gavage Studies). NTP, Research Triangle Park, NC.

Abstract: https://ntp.niehs.nih.gov/go/33584

Stefanski SA, Elwell MR, Stromberg PC. 1990. Spleen, lymph nodes, and thymus. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, 369-394.

Ward JM, Mann PC, Morishima H, Frith CH. 1999. Thymus, spleen, and lymph nodes. In: Pathology of the Mouse (Maronpot RR, ed). Cache River Press, Vienna, IL, 333-360.

All Images

Spleen - Congestion in a female F344/N rat from a chronic study. The red pulp sinusoids are moderately distended by erythrocytes (arrow).

Spleen - congestion in a female F344/N rat from a chronic study. The red pulp sinusoids are markedly distended by erythrocytes (arrow).

Authors and Reviewers

Authors

Kristen Hobbie, DVM, PhD
Principal Pathologist
Huntingdon Life Sciences
Peterborough, UK

Susan A. Elmore, MS, DVM, DACVP, DABT, FIATP
Staff Scientist, NTP Pathologist
NTP Pathology Group
National Toxicology Program
National Institute of Environmental Health Sciences
Research Triangle Park, NC

Holly M. Kolenda-Roberts, DVM, PhD, DACVP
Veterinary Pathologist
SNBL USA
Everett, WA

Reviewers

Jerrold M. Ward, DVM, PhD, DACVP, FIATP
Veterinary Pathologist
Global VetPathology
Montgomery Village, MD

Robert R. Maronpot, DVM, MS, MPH, DACVP, DABT, FIATP
Senior Pathologist
Experimental Pathology Laboratories, Inc.
Research Triangle Park, NC