Invasive breast carcinoma with ipsilateral axillary squamous carcinoma of unknown primary: A case report

Abstract

Introduction & importance
Invasive ductal carcinoma is the commonest primary breast carcinoma to metastasize to the axillary nodes. Squamous carcinoma (SCC) of the breast is seen rarely as a primary breast malignancy. Breast SCC with coexistent invasive ductal/lobular carcinoma as a ‘collision tumour’ is rare.

Case presentation
A 52-year-old Sri Lankan female presented with a right sided breast lump and ipsilateral cystic axillary mass. She was diagnosed with locally advanced invasive breast carcinoma and underwent neoadjuvant chemotherapy followed by mastectomy and axillary clearance where tumour infiltration of the brachial plexus was observed. Histology revealed two separate carcinomas; an invasive carcinoma of the breast and squamous carcinoma in the axilla. A squamous primary was not found despite evaluation. The patient developed recurrent axillary ulceration due to residual tumour and was transferred for oncological care.

Clinical discussion
This patient had a biopsy-proven invasive breast carcinoma with a cystic axillary mass with lymphadenopathy. This was concluded as locally advanced breast cancer. Pathological examination of the specimen indicated the presence of two separate malignancies of the breast and axilla. No evidence of squamous metaplasia or carcinoma of the breast was seen on histology, neither was a squamous primary identified on imaging or endoscopy. Neoadjuvant therapy may have caused resolution of the squamous component.

Conclusion
The presence of two separate cancers of varied histology in the breast and ipsilateral axilla in close proximity to each other is a rare phenomenon. Clinicians must be cautious not to misinterpret it as evidence of lymphatic spread.

Full text

International Journal of Surgery Case Reports 116 (2024) 109397
Available online 16 February 2024
2210-2612/© 2024 The Author(s). Published by Elsevier Ltd on behalf of IJS Publishing Group Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Case report
Invasive breast carcinoma with ipsilateral axillary squamous carcinoma of
unknown primary: A case report
Deshan Gomez
a
,
*
, Sanjeewa Seneviratne
b
a
University Surgical Unit – National Hospital of Sri Lanka, Colombo, Sri Lanka
b
Department of Surgery, Faculty of Medicine, University of Colomo, Sri Lanka
ARTICLE INFO
Keywords:
Squamous cell carcinoma
Breast cancer
Collision tumour
Two cancers
Case report
ABSTRACT
Introduction & importance: Invasive ductal carcinoma is the commonest primary breast carcinoma to metastasize
to the axillary nodes. Squamous carcinoma (SCC) of the breast is seen rarely as a primary breast malignancy.
Breast SCC with coexistent invasive ductal/lobular carcinoma as a ‘collision tumour’ is rare.
Case presentation: A 52-year-old Sri Lankan female presented with a right sided breast lump and ipsilateral cystic
axillary mass. She was diagnosed with locally advanced invasive breast carcinoma and underwent neoadjuvant
chemotherapy followed by mastectomy and axillary clearance where tumour inltration of the brachial plexus
was observed. Histology revealed two separate carcinomas; an invasive carcinoma of the breast and squamous
carcinoma in the axilla. A squamous primary was not found despite evaluation. The patient developed recurrent
axillary ulceration due to residual tumour and was transferred for oncological care.
Clinical discussion: This patient had a biopsy-proven invasive breast carcinoma with a cystic axillary mass with
lymphadenopathy. This was concluded as locally advanced breast cancer. Pathological examination of the
specimen indicated the presence of two separate malignancies of the breast and axilla. No evidence of squamous
metaplasia or carcinoma of the breast was seen on histology, neither was a squamous primary identied on
imaging or endoscopy. Neoadjuvant therapy may have caused resolution of the squamous component.
Conclusion: The presence of two separate cancers of varied histology in the breast and ipsilateral axilla in close
proximity to each other is a rare phenomenon. Clinicians must be cautious not to misinterpret it as evidence of
lymphatic spread.
1. Introduction
Invasive ductal carcinoma is the commonest type of breast cancer
and metastasizes commonly to the axillary nodes. Squamous cell carci-
noma (SCC) of the breast is a rare primary breast cancer which accounts
for <0.2 % of all breast malignancies with only a few reported cases
[1–3]. It has been described in combination with invasive ductal carci-
noma as a collision tumour. More rarely it has been seen in combination
with invasive lobular carcinoma of the same breast.
This is a case report of a patient with an invasive breast carcinoma
but with a concurrent axillary squamous carcinoma of unknown pri-
mary. This case has been reported in line with SCARE criteria [4].
2. Case presentation
A 52-year-old, postmenopausal, previously healthy, Sri Lankan
Sinhalese mother of 3 children presented to the surgical clinic with a
progressively enlarging right axillary lump of 2 months’ duration. She
had no signicant personal or familial risk factors for breast carcinoma.
On clinical examination, she had a 3x3cm clinically malignant right
breast lump in the 3–5 o’clock position with skin tethering and nipple
retraction, and a large 10x15cm cystic axillary lump with overlying
erythematous skin changes (Fig. 1). Bilateral mammography and breast
ultrasound revealed a BIRADS 5 lesion at the 3 o’clock position of the
right breast 1 cm from the nipple and multiple core biopsies were taken.
240 ml of straw-colored particulate uid was aspirated from the cystic
axillary lump and sent for cytological analysis. Core biopsy of the breast
lesion revealed a Nottingham grade II invasive breast carcinoma (NST),
which was Estrogen receptor (ER) +, Progesterone Receptor (PR) +,
Human Epidermal Growth Factor receptor (Her2Neu) -, Ki67–38 % on
immunohistochemical analysis. The ne needle aspirate of the axillary
lump was reported as a C2 benign smear and negative for malignant
* Corresponding author at: National Hospital of Sri Lanka, Colombo, Sri Lanka.
E-mail addresses: deshan.gomez@yahoo.com (D. Gomez), sanjeewa@srg.cmb.ac.lk (S. Seneviratne).
Contents lists available at ScienceDirect
International Journal of Surgery Case Reports
journal homepage: www.elsevier.com/locate/ijscr
https://doi.org/10.1016/j.ijscr.2024.109397
Received 6 January 2024; Received in revised form 9 February 2024; Accepted 12 February 2024

International Journal of Surgery Case Reports 116 (2024) 109397
2
cells. Staging contrast enhanced CT scan of the chest, abdomen and
pelvis revealed a locally advanced breast carcinoma with enlarged
ipsilateral axillary nodes without evidence of distant metastasis in the
thorax or abdomen. (T4N1M0).
Following a multi-disciplinary team discussion, she was referred for
neoadjuvant chemotherapy (NACT). She underwent 8 cycles of NACT
over a course of 6 months during which she developed ulceration of the
axillary lump. Restaging with CECT after completion of NACT revealed a
right sided locally advanced breast carcinoma in lower inner quadrant
measuring 3.8 cm, with ipsilateral axillary and internal mammary
lymphadenopathy without evidence of distant metastasis.
Right total mastectomy and level II axillary clearance was performed
by the General Surgeon under general anesthesia in the supine position.
Intraoperatively a large tumour mass was seen encasing the brachial
plexus and axillary vessels and was scooped out carefully. A suction
drain was inserted to the axilla and routine closure was performed. The
drain was removed on postoperative day 5 and the early postoperative
period was uncomplicated.
Histological examination of the specimen revealed a 25x22x15mm
Nottingham grade II invasive carcinoma of the breast no specic type
(NST) with high grade DCIS and perineural invasion but absent lym-
phovascular invasion with R0 resection margins, two reactive lymph
nodes and E cadherin membrane positivity on immunochemistry
(Fig. 2). The axillary mass did not contain lymph nodes as suspected but
was found to be a primary invasive keratinizing squamous cell carci-
noma with skin ulceration and focal involvement of the resection mar-
gins (Fig. 3). The axillary cavity was re-excised which revealed only
reactive reparative changes without residual tumour.
Search for a squamous primary did not yield fruitful results.
Macroscopic skin inspection of head, neck and thorax was normal, upper
gastro intestinal endoscopy and endoscopic evaluation of the naso-
pharynx, oropharynx, hypopharynx and larynx did not reveal suspicious
lesions. Transvaginal ultrasound scan revealed a slightly thickened
endometrium but the histology from the curettage was of only atrophic
endometrium. A relook of the post neoadjuvant CECT chest, abdomen
and pelvis was performed by the Consultant Radiologist in view of
scanning for a primary squamous lesion but was without success.
Re-excision of the axillary cavity, was complicated by the develop-
ment of a non-healing wound primarily due to residual and regrowth of
tumour locally. Further excisions were not possible due to risk of dam-
age to the brachial plexus. The patient was transferred to an oncology
unit 2 months after surgery for continuation of care and adjuvant
therapy.
3. Discussion
Invasive ductal carcinoma is the commonest type of breast cancer
and metastasizes commonly to the axillary nodes. Primary squamous
carcinoma (SSC) of the breast is very rare, and thought to originate from
mammary duct epithelium or from foci of squamous metaplasia within a
preexisting adenocarcinoma [5]. Approximately two thirds of these tu-
mours are cystic or have cystic components with central necrosis [6,7].
Diagnosis of SCC is reached when there are no other neoplastic com-
ponents such as ductal or mesenchymal elements in the tumour, the
tumour origin is independent of the nipple and absence of an associated
primary squamous cell carcinoma in a second site (oral cavity bronchus,
esophagus, renal pelvis, bladder, ovary, and cervix) [3]. Metastasis of
squamous cell carcinoma to the breast from other sites is more common
than primary breast SCC [8].
Squamous cell carcinoma of the breast has been described in com-
bination with invasive ductal carcinoma as a collision tumour but more
rarely it has been seen in combination with invasive lobular carcinoma
of the same breast [9]. There are a few case reports of squamous cell
carcinoma of the breast skin with invasive ductal carcinoma occurring as
a collision tumour [10].
In the above case, although the patient initially presented with a
cystic axillary lump, she was found to have an ipsilateral clinically
malignant breast lump and was diagnosed with an invasive breast car-
cinoma following core biopsy. Even though the aspirate of the axillary
lump was negative for malignant cells it was assumed that the axillary
lump was due to axillary lymph node metastasis from the primary breast
carcinoma. As the tumour was locally advanced, she was referred for
NACT and developed ulceration of the axillary lesion on completion of
therapy which was again thought to be due to poor treatment response
and progression of the locally advanced tumour.
Intraoperatively, the axilla contained what was assumed to be a
lymph node mass that encased the brachial plexus and axillary vessels
which had to be scooped out in order to preserve these structures. It was
only during histological examination of the surgical specimen that it was
noted that the axillary mass did not contain lymph nodes but was rather
a primary axillary squamous carcinoma. The mastectomy specimen was
conrmed as invasive breast carcinoma NST without evidence of
metaplastic squamous cell carcinoma. It contained 2 lymph nodes which
were free of tumour. The two tumours were separate with no evidence of
collision or connection between the two components.
Since she was post NACT, the microscopic architecture of the carci-
noma had varied and there was difculty in differentiating if it was
ductal or lobular carcinoma with the appearance more in keeping with
lobular carcinoma. E-cadherin immunochemistry is useful in classifying
cases of breast cancer with indeterminate histological features. Negative
E-cadherin stain is a sensitive and specic biomarker to conrm invasive
lobular carcinoma [11]. Since the specimen stained positive for E-cad-
herin, the breast lesion was reported as invasive breast carcinoma NST.
Although rare, there are several case reports that describe pure
squamous cell carcinoma of the breast, squamous cell carcinoma else-
where metastasizing to the breast and squamous carcinoma occurring
Fig. 1. Initial presentation with clinically malignant breast lump and cystic axillary mass.
D. Gomez and S. Seneviratne

International Journal of Surgery Case Reports 116 (2024) 109397
3
concurrently with primary breast ductal or lobular carcinoma
[1–3,6–9]. This patient had two separate tumours presumably of two
separate origins occurring concurrently adjacent to each other in the
breast and axilla which has not been reported previously.
Pathological examination of the mastectomy specimen did not reveal
and area of squamous metaplasia or squamous carcinoma. In-
vestigations such as contrast enhanced CT of the chest, abdomen, pelvis,
rhinoscopy, laryngoscopy, bronchoscopy, Oro gastroduodenoscopy and
transvaginal ultrasound failed to demonstrate a possible primary squa-
mous lesion.
Since this patient had 8 cycles of neoadjuvant chemotherapy, it is
possible that there had been primary squamous lesion in the breast or
elsewhere that responded to the therapy. Nonetheless, the presence of
two separate primary tumours in the breast and ipsilateral axilla, of two
separate origins occurring close to each other within the territory of
lymphatic drainage can be easily mistaken for and mimics lymphatic
spread from a breast primary. This is a unique situation that has not been
reported in literature previously.
Fig. 2. Post NACT residual invasive carcinoma of the breast NST with high grade DCIS and perineural invasion.
Fig. 3. H&E of the axillary mass showing keratinizing squamous cell carcinoma with skin ulceration and focal involvement of the resection margins.
D. Gomez and S. Seneviratne

International Journal of Surgery Case Reports 116 (2024) 109397
4
4. Conclusion
The presence of two separate cancers of different histology, in the
breast and ipsilateral axilla in close proximity to each other is a rare
phenomenon and has not been reported. It must be kept in mind as it can
be easily misinterpreted as evidence of lymphatic spread.
Consent for publication
Written informed consent was obtained from the patient for their
anonymized information to be published in this article. A copy of the
written consent is available for review by the Editor-in-Chief of this
journal on request.
Ethical approval
Ethical approval was deemed unnecessary by the institutional ethics
committee as the paper reports a single case that emerged during normal
practice.
Funding
This research received no specic grant from any funding agency in
the public, commercial, or not-for-prot sectors.
Author contribution
Deshan Gomez: Conceptualization, Writing – original draft, Writing –
review and editing, Visualization.
Sanjeewa Seneviratne: Writing – review and editing.
Guarantor
Deshan Gomez
Declaration of competing interest
The author(s) declare(s) that there is no conict of interest.
Acknowledgments
Not applicable.
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