Synchronous primary breast carcinoma: A case report

INTRODUCTION

Synchronous bilateral breast cancer is defined as the presence of primary malignant tumors in both breasts diagnosed simultaneously or within a 6-month interval of the first diagnosis. It is considered an uncommon clinical presentation, accounting for less than 2% of all breast cancer cases.^[1,2] Early and accurate diagnosis is very crucial for guiding appropriate treatment and avoiding misinterpretation. With this case, we share our experience of diagnosing synchronous bilateral invasive ductal carcinoma with distinctive imaging findings and histopathological confirmation.

CASE REPORT

A 42-year-old female presented with palpable lumps in both breasts since the past 3 months. No significant family history of breast carcinoma was present. No history of pain or nipple discharge was provided. Clinical examination revealed firm, non-mobile masses in both breasts with normal-appearing skin and nipples. The patient underwent mammography for further evaluation. A full-field digital mammogram revealed an American College of Radiology category C type breast (heterogeneously dense parenchyma) with the presence of a round, equal-to-high-density mass showing indistinct margins in the upper outer quadrant of the right breast. It measured approximately 20.6 mm × 15.6 mm in size [Figure 1].

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Figure 1:

(a) Mediolateral oblique and (b) craniocaudal view mammogram of both breast showing round equal to high density mass with indistinct margins in upper outer quadrant of right breast and round oval shaped equal density mass with circumscribed margin in lower outer quadrant of right breast. A round high density mass with spiculated margins seen in central quadrant of left breast.

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Another round isodense mass measuring approximately 14.4 mm × 13.2 mm in size with circumscribed margins was noted in the lower outer quadrant of the right breast [Figure 1].

In the left breast, a round, high-density mass with spiculated margins was seen in the central quadrant, measuring approximately 23 mm × 27 mm in size. No associated features like nipple retraction, skin thickening, or architectural distortion were seen in either breast [Figure 1].

Corroborative ultrasound of the right breast revealed an approximately 20 mm × 15 mm sized hypoechoic mass with non-circumscribed margins (microlobulated and partly indistinct on the right lateral aspect) and mixed posterior features (acoustic shadowing and enhancement) in the upper outer quadrant at the 9–10 o’clock position, 43.2 mm from the nipple and 7 mm deep to the skin, and was assigned as breast imaging reporting and data system (BIRADS) category 4c [Figure 2a-b]. Another oval hypoechoic mass with a circumscribed margin measuring approximately 17.2 mm × 11.9 mm in size was noted in the lower outer quadrant 24.1 mm away from the nipple and 2.5 mm deep to the skin and was assigned as BIRADS cat 3.

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Figure 2:

(a) Ultrasonography images of right breast showing hypoechoic mass with not circumscribed margins (micro lobulated and partly indistinct on right lateral aspect) and mixed posterior features (acoustic shadowing and enhancement) in upper outer quadrant (red line). (b) Ultrasonography images of right breast showing hypoechoic mass with not circumscribed margins, mixed posterior features and minimal internal vascularity (red arrow).

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On the left breast, approximately 25.4 mm × 20 mm sized hypoechoic anti-parallel oriented mass with angular margins and mixed posterior features (posterior acoustic shadowing and enhancement) was seen in the retroareolar region at 12 o’ clock (BIRADS category 4c) [Figure 3a-b].

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Figure 3:

(a) Ultrasonography images of left breast showing hypoechoic mass with angular margin (red arrow) and mixed posterior features (posterior acoustic shadowing and enhancement) in retro areolar region. (b) Ultrasonography images of left breast showing hypoechoic mass with angular margin and posterior acoustic shadow with minimal internal vascularity (red arrow) in retro areolar region.

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Ultrasound of bilateral axilla revealed a few round lymph nodes, the largest measuring approximately 11.8 mm × 8.8 mm with eccentric cortical thickening of 6.4 mm [Figure 4]. On the right axilla, normal-sized lymph nodes with maintained fatty hilum were seen.

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Figure 4:

(a) Ultrasonography showing round left axillary lymph node with effaced fatty hilum and smooth cortical thickening. (b) Ultrasonography images of left axillary lymph node showing cortical thickening (red arrow).

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Core needle biopsy of both BIRADS cat 4c mass, right breast mass at 9–10 o’ clock position, and left breast mass at retroareolar region 12 o’ clock position was done, which confirmed the diagnosis of invasive carcinoma of no special type (ductal) [Figure 5a-b]; Histologic Grade (Nottingham Histologic Score): Grade 2 (total score 6) in both breasts. An immunohistochemistry profile was sent which showed estrogen receptor (ER) positive and progesterone receptor (PR) and Her-2/neu negative. Ki-67-< 14%, suggestive of luminal type A breast carcinoma for both breast masses.

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Figure 5:

(a) Histopathological (H and E stain) images of right breast (20 x magnified) mass showing cells that are larger than normal. Open vesicular nuclei, visible nucleoli, and moderate variability in both size and shape of cells seen. (b) Histopathological (H and E stain) images of left breast (10 x magnified) mass showing cells that are larger than normal. Open vesicular nuclei, visible nucleoli, and moderate variability in both size and shape of cells seen.

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A contrast-enhanced computed tomography scan of the chest and a methyl diphosphonate (99m Tc MDP) bone scan were performed to evaluate for distant metastasis. No evidence of any pulmonary or osseous metastases was reported. The findings supported the diagnosis of synchronous primary breast carcinoma.

DISCUSSION

Synchronous bilateral carcinoma of the breast is rare, with a diagnostic challenge with an incidence rate of 1%–3%. Positive family history, multicentric nodules, and lobular histology type are factors associated with increased risk of developing bilateral breast cancer.^[3] Ultrasound imaging characteristics of both masses, including hypoechoic texture, non-parallel orientation, non-circumscribed margins, posterior shadowing, and axillary adenopathy, were consistent with malignant features. Axillary lymphadenopathy further emphasized the importance of regional nodal evaluation. Accurate differentiation between synchronous primaries and contralateral metastasis is critical for determining prognosis and therapeutic approach. In this case, the lack of metastatic disease elsewhere on the computed tomography (CT) and bone scan and the distinct anatomical locations of the breast mass supported the diagnosis of synchronous primary carcinoma. Studies have shown that there was no significant difference in survival for patients with bilateral compared to unilateral breast cancer,^[4] but synchronous tumors were associated with poor survival in comparison to metachronous tumors.^[5] Synchronous primary breast cancers can show differences in their somatic genetic alterations in the absence of systemic therapy; hence, biopsies of masses in both breast are necessary. Mutational signature could be a factor contributing to spatial intratumor genetic heterogeneity.^[6] With a higher molecular subtype concordance rate and a less disease-specific survival rate, these patients should promptly receive treatment.^[7,8]

Magnetic resonance imaging, being the most sensitive imaging modality, not only helps in preoperative planning but also helps in the determination of other multicentric/multifocal nodules.^[9]

CONCLUSION

In this case, the significance of a comprehensive bilateral breast and axillary evaluation in those presenting with multiple masses in both breasts is highlighted. Synchronous primary breast cancer, though rare, should be considered in every patients presenting with lump in both breast. Multimodal imaging combined with histopathology is essential for definitive diagnosis and staging. Bilateral multiple breast nodules are not always benign. If any suspicious features are seen, a histopathological correlation must be warranted from both breast.