Nervous System

Brain, Leptomeninges - Hamartoma, Lipomatous

Narrative

Comment:

Figure 1 depicts a neurodevelopmental anomaly. This midline leptomeningeal lipomatous hamartoma is located at the base of the cingulate gyrus, immediately above the corpus callosum and septal nuclei. Consisting of normal white adipocytes, it is in the common location for a lipomatous hamartoma. The expansion of the hamartoma has had little compressive effect on adjacent structures and was not accompanied by noticeable clinical neurological signs. This type of hamartoma is uncommon in rodent studies. It is not to be confused with a lipoma or liposarcoma.

Recommendations:

Lipomatous hamartomas should be diagnosed in NTP studies and the subsite specified.

References:

Krinke GJ, Kaufmann W, Mahrous AT, Schaetti P. 2000. Morphologic characterization of spontaneous nervous system tumors in mice and rats. Toxicol Pathol 28:178-192.

Abstract: http://www.ncbi.nlm.nih.gov/pubmed/10669006

All Images

Leptomeningeal lipomatous hamartoma in an untreated male B6C3F1 mouse from a 2-year study. The arrow identifies the location of the lipomatous mass.

Authors and Reviewers

Authors 

Peter Little, DVM, MS, PhD, DACVP
Neuropathology Consultant
Experimental Pathology Laboratories, Inc.  
Research Triangle Park, NC

Deepa B. Rao, BVSc, MS, PhD, DABT, DACVP
NTP Pathologist (Contractor)
Integrated Laboratory Systems, Inc.
Research Triangle Park, NC

Reviewers

James P. Morrison, DVM, DACVP
Scientific Director
Charles River Laboratories, Pathology Associates
Research Triangle Park, NC

Robert C. Sills, DVM, PhD, FIATP
Chief, Cellular and Molecular Pathology Branch
National Toxicology Program
National Institute of Environmental Health Sciences
Research Triangle Park, NC