Case Presentation
A 72-year-old Caucasian postmenopausal woman was evaluated for a
palpable right axillary mass that she had identified on self-examination
approximately two weeks prior to presentation. The mass was non-tender
and not associated with nipple discharge or any systemic symptomatology.
The patient was G2P2, with menarche at age 10 and menopause at age 50.
She reported a family history significant for a diagnosis of breast
cancer in her sister at age 41 and niece at age 53. There was no family
history of ovarian cancer. Of note, the patient’s sister had negative
BRCA testing. Physical examination revealed a slightly mobile mass in
the right axilla located about 6 cm below the axillary crease and 1.5 cm
anterior to the mid-axillary line. The patient had a thin body habitus,
and the right axillary mass was located essentially in the subcutaneous
layer of the skin. There was no adenopathy in the right axilla or in the
bilateral cervical or supraclavicular regions. A bilateral diagnostic
mammogram showed a spiculated mass measuring 0.9 cm in diameter in the
extreme axillary tail of the right breast that corresponded with the
palpable mass found on physical examination (Figure 1). An ultrasound of
the right axilla demonstrated a hypoechoic, irregular mass with
spiculated margins measuring 0.9 x 0.7 x 1.3 cm that was surrounded by
marked vascularity (Figure 2). No abnormal lymph nodes were identified
on mammogram or ultrasound. These findings were assigned a BI-RADS 4
classification.
An ultrasound-guided core needle biopsy revealed a grade 2 invasive
lobular carcinoma (ILC) that was ER-positive (95%), PR-negative (0%),
and HER2/neu-positive by fluorescence in situ hybridization. A bilateral
breast MRI was performed to rule out the presence of any other breast
abnormalities. Representative T1 fat saturated post-contrast sagittal
and coronal breast MRI images demonstrated an irregular enhancing mass
in the right axilla (Figure 3) consistent with biopsy-proven ILC but was
otherwise negative. Ultimately, the patient was determined to have a
stage IA (cT1cN0) breast cancer.
After consultation with the breast medical oncology team, the patient
underwent wide local excision of the right axillary mass with SLN
biopsy. One hour prior to surgery, the patient was injected with 400 mCi
of technetium-99m (Tc-99m) sulfur colloid. One-third of the dose was
injected intra-dermally into the skin overlying the mass, one-third was
injected directly into the mass, and the remaining third was injected
into the subcutaneous tissue underneath/posterior to the mass. At the
time of operation, the right axilla was examined and the position of the
mass was noted 6 cm inferior to the axillary crease. The axilla was
scanned, and an area of increased counts was identified just superior to
the tumor in the mid-axillary line. An elliptical incision was created
over the mass and deepened with cautery. The tumor was resected along
with an ellipse of overlying skin and a rim of normal adipose tissue
measuring approximately 1 cm. Additional shave margins were taken. The
posterior border of the tumor consisted of the pectoralis major muscle,
the fascia of this muscle having been included in the primary specimen.
The axilla was scanned, and an area of increased counts was identified
just under the pectoralis minor muscle against the chest wall. The
clavipectoral fascia was incised and a 1 cm lymph node was identified
and removed. Ex vivo this lymph node had counts over 900. It was
sent for frozen section and ultimately came back positive for metastatic
lobular carcinoma. The entire axilla was re-scanned and no other areas
of tracer uptake were identified. No suspicious lymph nodes were found
by palpation or inspection. The decision was made to forego axillary
dissection given existing evidence showing that subsequent radiation
therapy alone would be sufficient for control of the axilla.(3)
Pathologic evaluation of the lymph node revealed macrometastatic
carcinoma measuring 7 mm in diameter without extranodal extension.
Regarding the primary tumor, pathologic evaluation revealed a grade 2,
ER-positive, PR-negative, and HER2/neu-positive ILC measuring 1.6 cm in
maximum diameter. Final margins were negative.
The patient tolerated the procedure well with no post-operative
complications. She is now disease-free 6 months following surgery. She
received six cycles of adjuvant chemotherapy consisting of a regimen of
docetaxel, carboplatin, trastuzumab and pertuzumab. This treatment was
followed by whole breast radiation therapy and maintenance
pertuzumab/trastuzumab.