Subcutaneous nodules at the injection site of low-molecular-weight heparin: a mimic of metastatic disease at CT.
OBJECTIVE
To describe the appearance and prevalence of subcutaneous nodules in the anterior abdominal wall seen at CT in cancer patients receiving subcutaneous injections of low-molecular-weight heparin (LMWH).


METHODS
CT examinations were reviewed in 426 patients receiving subcutaneous abdominal wall injections of LMWH for the presence of nodules. Nodules were evaluated for contour, maximal diameter, CT attenuation, and presence of hazy changes or air in the surrounding fat.


RESULTS
Fourteen (3%) of the 426 patients had nodules attributable to subcutaneous injections of LMWH. Findings included poorly defined borders (100%), adjacent hazy soft tissue changes (100%), adjacent air (57%), and a mean CT attenuation of -4.4 HU (range: -50-40 HU). Three (0.7%) of 426 patients had nodules caused by metastatic disease. One (33%) nodule had poorly defined borders, two (67%) had surrounding hazy changes, one (33%) had air in adjacent tissue, and there was a mean CT attenuation of 44 HU (range: 14-140 HU). One (0.2%) patient had a subcutaneous nodule of uncertain etiology.


CONCLUSIONS
Patients receiving subcutaneous injections of LMWH may develop nodules at the injection sites. Such nodules can resemble metastatic tumor deposits at CT, and careful correlation with clinical history and growth trends of metastatic deposits elsewhere in the patient is needed to avoid misdiagnosis.
Funt
Stacey A
SA
Department of Radiology, Memorial Sloan-Kettering Cancer Center, Hospital Vall d'Hebron and Centro Medico Teknon, Barcelona, Spain. funts@mskcc.org
Hidalgo
Alberto
A
Panicek
David M
DM
D000009:Abdominal Muscles / Q000000981:diagnostic imaging / Q000187:drug effects*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D003875:Drug Eruptions / Q000000981:diagnostic imaging*; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000139:chemically induced / Q000000981:diagnostic imaging; D007279:Injections, Subcutaneous / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D014057:Tomography, X-Ray Computed
D006495:Heparin, Low-Molecular-Weight