Key words
Fat necrosis - breast - extravasation - mammography - sonography
Schlüsselwörter
Lipoidnekrose - Mamma - Paravasat - Mammografie - Ultraschall
Introduction
Chemotherapeutic agents are usually administered via a surgically inserted,
permanent, subcutaneous port. The port is implanted prepectorally through a skin
incision, and the connected catheter is introduced through the subclavian vein into
the superior vena cava using the Seldinger technique. This transcutaneous
cannulation allows medication or parenteral nutrition to be infused through a
central venous line over longer periods of time.
Possible complications include infections, thrombosis, dislocation or extravasation
of highly toxic chemotherapeutic agents. Depending on the chemical properties of the
chemotherapeutic agent this can result in severe local damage. In the literature,
the incidence of extravasation is reported to range between 0.1 and 6.5 %.
Recommended immediate measures are stopping the infusion, aspiration of the
extravasation, local infiltration with the specific antidote and heat treatment or
cold compresses [1], [2]. In
some cases, particularly in the event of an extravasation with a high tissue
toxicity, rapid surgical intervention may be necessary.
Folinic acid (synonyms: citrovorum factor, leucovorin; formula:
C20H23N7O7) is a tetrahydrofolic
acid derivative used in the treatment of colorectal cancer for its synergistic
effect in combination with the cytostatic drug 5-fluorouracil (5-FU) [3]. Folinic acid and folic acid may also be administered as
an antidote in treatments using folic acid antagonists such as methotrexate (MTX)
to
reduce the risk of an adverse drug reaction (ADR) and, in particular, to reduce
hematopoetic toxicity (so-called “leucovorin rescue”) [4].
Case Report
We report here on a 58-year-old patient with abnormal findings in the left breast
on
screening mammography (October 2012).
In May 2008 the patient was diagnosed with rectal cancer (pT3, pN0 [0/25], M0),
subsequently treated by surgical resection (deep anterior rectal resection) followed
by radiochemotherapy. Chemotherapy (5-fluorouracil) was delivered through a
surgically implanted port, placed prepectorally on the left side. In September 2011,
after computed tomography (CT) examination the patient was diagnosed with peritoneal
cancer with a suspicion of abdominal wall metastasis, subsequently confirmed by
histological analysis. The patient was started on palliative chemotherapy (FOLFOX4
regimen + bevacizumab), during which extravasation of folinic acid occurred. As the
peritoneal cancer continued to progress, the treatment regimen was switched in March
2012 to irinotecan + bevacizumab. Secondary diagnoses included morbid obesity and
Gravesʼ disease treated 10 years previously with radioiodine. The patient had not
previously undergone breast surgery.
The abnormal finding in the left breast was located at the 1–2 oʼclock position. The
mammogram showed extensive (11 × 4 cm) hyperdense nodules with predominantly round,
fine granular calcifications ([Fig. 1]). On sonography,
the findings presented as a hypoechogenic, inhomogenous, partially diffuse, partly
solid, partly cystic mass measuring 3.3 × 1.0 × 3.0 cm, with individual
calcifications and reduced echogenicity in the dorsal aspect. The findings were
located 7 cm from the nipple and 2 mm under the skin ([Fig. 2]). Strong densification of the left breast was found at the
corresponding position on palpation. The subcutaneous port could be palpated
immediately cranial to the densification. On CT done during follow-up for rectal
cancer, new streaky/pitted densifications were noted in the left breast ([Fig. 3]).
Fig. 1 Bilateral mammography done in 2 projections (MLO, CC) with
Cleopatra view of the left breast. Extensive hyperdense nodules and
predominantly round, fine granular calcifications are visible in the left breast
(1–2 oʼclock position) due to fat necrosis after folinic acid extravasation.
Prepectoral port chamber access is visible on the left. Normal right breast.
Fig. 2 a and b Sonographic imaging of the left breast. Mass located
7 cm from the nipple and 2 mm under the skin measuring 3.3 × 1.0 × 3.0 cm. The
image shows a hypoechogenic, inhomogenous, partly solid, partly cystic,
partially diffuse mass with individual calcifications and reduced dorsal
echogenicity (a axial plane; b sagittal plane).
Fig. 3 a and b Axial, contrast-enhanced computed tomography (CT)
thoracic image (soft reconstruction kernel, soft-tissue window setting). New
streaky/pitted densifications due to fat necrosis are visible in the left breast
(b). a shows the unremarkable appearance of the same area
prior to folinic acid extravasation.
Based on the patientʼs previous history and the results of the breast diagnostics,
a
diagnosis of extensive fat necrosis after folinic acid extravasation was made
(BI-RADS II). No further measures were taken. The patient will continue to be
screened using mammography.
Discussion
Fat necrosis of the breast is a benign lesion caused by iatrogenic (surgical
intervention, biopsy, oral radiotherapy) or non-iatrogenic trauma [5], [6]. Clinically the course is
generally unremarkable, but fat necrosis can manifest itself in the form of soft or
compact fixed nodules extending to the overlying skin [7].
The extremely varied morphological characteristics of fat necrosis have been
investigated and described in detail in the literature, and a good knowledge of its
characteristic images in mammography and sonography is important to differentiate
fat necrosis from malignant lesions which may have a similar appearance [8], [9]. Typical findings on
mammography are oleocysts, round or asymmetrical focal findings and structural
distortions. Coarse calcifications and, more rarely, clusters of pleomorphic
micro-calcifications can occur. Common sonographic findings are solid, hypoechogenic
focal findings with reduced echogenicity in the dorsal aspect, echo-free focal
findings with increased dorsal echogenicity or dorsal sonic shadow, or echogenic
cystic focal findings with hyperechogenic subcutaneous tissue. In rare cases,
mammography and/or sonography show no abnormal findings despite positive clinical
findings. The morphology of the necrotic area often changes over time, with
mammography showing an increase in coarse calcifications. To our knowledge, there
are no previous reports on the appearance of an extravasation in the breast.
This case demonstrates the importance of careful anamnesis and of a thorough
documentation of all therapeutic measures performed together with any complications.
The information can be of crucial importance when making the diagnosis and can help
reduce the number of unnecessary biopsies. In cases with unclear findings, a further
diagnostic workup may be necessary using magnetic resonance tomography (MRT) or
biopsy with histological assessment.
Steps
-
Careful consideration of the patientʼs prior medical history is very
important in breast diagnostics and may often be decisive for the correct
diagnosis.
-
A good knowledge of the mammographic and sonographic features of fat necrosis
can reduce the number of unnecessary biopsies.
