An unusual case of breast cancer masked by hidradenitis suppurativa

INTRODUCTION

Breast cancer is the most frequently diagnosed cancer among women in the United States and is the most common solid organ tumor to metastasize to the skin.^[1] When compared to other racial and ethnic groups, African–American women are more likely to have aggressive cancers at younger ages and sometimes even earlier than the screening age.^[2] We share a unique case of a young African–American female who presumed that her breast mass was secondary to her known chronic condition of hidradenitis suppurativa (HS), leading to a delay in seeking care and thereafter presenting with a solitary distant metastasis from breast cancer.

Locally advanced breast cancer or inflammatory breast cancer can sometimes mimic infectious or inflammatory dermatologic conditions involving the breast. Therefore, in cases with mastitis or breast abscess, follow-up examinations and imaging after initial treatment are important to ensure improvement and resolution. If symptoms and signs persist after treatment for mastitis and breast abscess, biopsy or fine-needle aspiration should be performed to exclude or diagnose malignancy. Inflammatory skin conditions, such as HS, when they involve the breast and axillary skin, should also be similarly clinically followed and re-evaluated.

CASE REPORT

A 28-year-old African–American woman presented to the emergency department (ED) with back pain. She had a long-standing history of HS affecting the axilla, groin, inframammary folds, and central chest, with recurrent infections, scarring and multiple incisions, and drainage procedures since she was a teenager. Computed tomography (CT) of the chest ordered in the ED demonstrated bilateral breast and axillary masses, and a destructive lesion of T5 body and pedicles, with extension into the spinal canal and mild indentation to the cord. She was admitted to the hospital and a vertebroplasty was performed. The vertebral biopsy revealed metastatic carcinoma.

On further inquiry, the patient stated that she had felt masses in the right breast for 2 months, but she believed that they were related to the recurrent abscesses and inflammation related to HS. She was discharged from the hospital after an uneventful post-vertebroplasty hospital course.

Immediate outpatient diagnostic breast imaging, including bilateral mammogram and bilateral breast ultrasound studies, was then performed [Figure 1a-d and 2a-e]. In the right breast, there were multiple suspicious masses from 8 to 9’o clock, 6–9 cm from the nipple. In the right axilla, there were multiple enlarged and cortically thickened lymph nodes. The left axillary masses were intradermal on imaging, consistent with known HS. In addition, there was a reactive intra-mammary lymph node in the outer left breast. Overall, the diagnostic work-up was given a Breast Imaging Reporting and Data System Breast Imaging Reporting and Data System (BI-RADS)-5 assessment, highly suggestive of malignancy, considering the right breast findings. Subsequently, three image-guided biopsies were performed: for two dominant right breast masses and for the most enlarged right axillary node. The pathology results showed invasive ductal carcinoma (IDC) for both right breast masses and metastatic carcinoma in the lymph node. The IDC was shown to be poorly differentiated, estrogen receptor positive, progesterone receptor positive, and human epidermal growth factor receptor 2 negative.

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Figure 1:

A 28-year-old-female with multiple bilateral breast masses diagnosed with invasive ductal carcinoma. (a) Two-dimensional craniocaudal view of the right breast demonstrates multiple masses in the outer central breast (white arrows), approximately 5-6 cm from the nipple. Largest mass (arrowhead) is identified in the posterior depth overlying the pectoralis muscle. Trabecular edema is noted medial and inferior to the masses (white star). (b) Two-dimensional mediolateral oblique view of the right breast again demonstrates multiple masses in the outer central breast (white arrows), approximately 5-6 cm from the nipple. Largest mass (arrowhead) is identified in the posterior depth overlying the pectoralis muscle. Trabecular edema is noted medial and inferior to the masses (white star). (c) Two-dimensional mediolateral oblique view of the left breast demonstrate an oval circumscribed mass (white arrow) in the outer posterior breast, approximately 8 cm from the nipple. (d) Two-dimensional craniocaudal view of the left breast again demonstrates an oval circumscribed mass (white arrow) in the outer posterior breast, approximately 8 cm from the nipple.

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Figure 2:

A 28-year-old-female with multiple bilateral breast masses diagnosed with invasive ductal carcinoma. (a) Targeted ultrasound of the right breast at 8’O clock, 7 cm from the nipple, demonstrates the dominant posterior mass (white arrow) with indistinct margins abutting the pectoralis muscle. (b) Targeted ultrasound of the right breast at 9’O clock, 8 cm from the nipple, demonstrates solid mass with microlobulated margins (white arrow). (c) Targeted ultrasound of the right axilla demonstrates enlarged and cortically thickened axillary lymph node (white arrow) at 17 cm from the nipple. (d) Targeted ultrasound of the left breast at 3’O clock, 7 cm from the nipple, demonstrates enlarged benign appearing, likely reactive, intramammary lymph node (white arrow), which corresponds to the circumscribed mass seen on the mammogram. (e) Ultrasound of the left axilla demonstrates intradermal hypoechoic lesions (white arrow), which appear inflammatory consistent with patient’s known history of hidradenitis suppurativa.

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Supplemental imaging was subsequently performed to evaluate disease extent. Magnetic resonance imaging (MRI) of the breasts [Figures 3a-c and 4a-c] demonstrated multiple masses with intervening non-mass enhancement in the lower outer right breast, with an antero-posterior span of 11.5 cm, extending from 4 cm from the nipple to the chest musculature, with enhancement extending into the pectoralis muscle. In addition, there were enlarged level 1 and level 2 right axillary nodes, bilateral prominent internal mammary nodes as well as pre-vascular space mediastinal nodes. There were changes in extensive HS involving both breasts and axillae, and there were no signs of malignancy in the left breast. MRI was helpful at highlighting the differences between the “gray signal of cancer” and the “bright white signal of inflammation” related to HS, on short tau inversion recovery (STIR) sequence. Positron emission tomography/ CT (PET/CT) showed hypermetabolic activity in the areas of disease identified by MRI, including in the bilateral internal mammary nodes, pre-vascular space mediastinal nodes, and in T5; however, no other distant disease was identified [Figure 5a-c]. PET/CT showed hypermetabolic activity in both areas of cancer and inflammation. She is now on palliative intent endocrine treatment and chemotherapy, considering her clinical Stage IV disease.

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Figure 3:

A 28-year-old-female with multiple bilateral breast masses diagnosed with invasive ductal carcinoma. (a) Magnetic resonance imaging (MRI) of the breasts- short tau inversion recovery (STIR) sequence demonstrates heterogeneous T2-intermediate signal intensity (gray area) mass (white arrow). Additionally, there are areas of high T2 signal intensity (white area) within bilateral breasts and intermammary region suggesting inflammation (white arrowheads) from patient’s known history of hidradenitis suppurative (HS). (b) Post-gadolinium images demonstrate heterogenous intense enhancement of the masses (straight and curved white arrows) within the right breast with intervening contiguous non-mass enhancement (white asterisk) extending from 4 cm from the nipple to the chest musculature. There is loss of fat plane between the posterior mass and pectoralis and the enhancement extends to the pectoralis muscle (white arrowhead). The posterior mass is the largest and demonstrates central necrosis (straight white arrow). (c) Post-gadolinium image highlighting findings of inflammatory changes secondary to HS (white arrows).

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Figure 4:

A 28-year-old-female with multiple bilateral breast masses diagnosed with invasive ductal carcinoma. (a & b) Magnetic resonance imaging- short tau inversion recovery (STIR) sequence demonstrates multiple enlarged level 1 and level 2 right axillary lymph nodes (white arrows in 4a) and enlarged internal mammary lymph node (white arrowhead in 4b). (c) Post-gadolinium image demonstrate prominent pre-vascular space mediastinal lymph node (white arrow).

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Figure 5:

A 28-year-old-female with multiple bilateral breast masses diagnosed with invasive ductal carcinoma. (a) Coronal view of positron emission tomography-computed tomography (PET-CT) of the chest demonstrate the dominant posterior right breast mass (white arrow) with maximal standardized uptake volume (SUV) of 6.0. Additional mass is identified more laterally (white arrowhead) with maximal SUV of 6.3. (b) Axial view of PET-CT at the level of aortic arch demonstrate conglomerate right axillary lymphadenopathy (white arrow) with maximal SUV of 9.1. (c) Sagittal view of computed tomography on bone window shows compression fracture of the T5 vertebra (white arrow) for which the patient underwent kyphoplasty.

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DISCUSSION

HS is a chronic inflammatory disorder affecting the apocrine glands, resulting from follicular blockage in the surrounding epithelium. HS significantly affects quality of life, particularly in young adults, manifesting as recurrent painful nodules, inflammatory abscesses, fistulas, sinuses, and scarring, typically in areas such as the axilla, breasts, buttocks, and groin.^[3-7] African-Americans are more likely to develop HS than other races.^[3] The condition is associated with various comorbidities, such as obesity, acne, polycystic ovary syndrome, hyperlipidemia, and depression. Furthermore, patients with HS may also experience primary cutaneous cancers, hematologic malignancies, and solid tumors.^[4,8,9]

In this case report, a 28-year-old African–American woman with known HS presented with back pain and was ultimately diagnosed with stage IV metastatic breast cancer. The diagnosis was delayed due to masking by chronic HS lesions. Similarly, prior case reports have shown abscesses or mastitis concealing and delaying the timely diagnosis of underlying cancers.^[10,11]

Clinicians should be cautious in immediately attributing any new breast or axillary skin lesion to infection or inflammation. The classic presentation of infectious breast condition is a painful breast lesion in the setting of fever and elevated white blood cell count. A thorough history and clinical evaluation should precede assumptions of benign etiology in atypical presentations. Lactation is a risk factor for mastitis and breast abscesses, and other common associations are with co-morbidities such as diabetes, tobacco use, and obesity. On the other hand, any breast lesion in high-risk patients with known risk factors for breast cancer, such as personal or family history of breast cancer, BReast CAncer (BRCA) gene gene mutations, history of chest radiation, should be considered suspicious and investigated thoroughly. HS typically presents as recurrent, painful, subcutaneous nodules with sinus tract formation, scarring, and purulent drainage, and the lesions are frequently bilateral. In contrast, breast cancer usually presents as a firm, non-tender, irregular, and unilateral mass. Furthermore, in patients with HS, mastitis, or abscess, if a lesion over the breast does not respond to appropriate treatment, a diagnostic mammogram, targeted ultrasound, and, if needed, biopsy should be performed.

On imaging, the presence of complex cystic solid masses, internal vascularity, irregular margins, no change or interval growth despite antibiotic treatment, is the signs that indicate neoplastic etiologies over infectious or inflammatory etiologies. Advanced imaging, especially STIR sequences of MRI, can be helpful in differentiating inflammation and cancer in some cases. The tissue involved with cancer demonstrates dirty gray signal whereas the areas of inflammation demonstrate bright white signal.^[7] The final diagnosis is through histopathologic examination of image-guided biopsies. This is especially necessary in cases which are diagnostic dilemmas.

The American College of Radiology (ACR) recommends annual screening with mammogram beginning at age 40 for women of average risk and earlier and/or more intensive screening for women at higher-than-average risk. As per ACR, all women should undergo risk assessment by age 25, especially black women and women of Ashkenazi Jewish heritage, so that those at higher-than-average risk can be identified and appropriate screening initiated.^[12] Our patient got diagnosed with Stage IV breast cancer at an age earlier than the screening age for mammogram. With more intense risk assessment, more women could potentially be detected at earlier stages of breast cancer, leading to improved prognoses.

CONCLUSION

Invasive breast cancer can resemble infectious or inflammatory skin conditions like HS, leading to delays in diagnosis. A detailed history and physical examination are critical to evaluate any new breast mass, even in patients with chronic skin conditions. In high-risk or atypical clinical scenarios, further evaluation with dedicated breast imaging should be performed. Suspicious findings on breast imaging should be followed by a biopsy to evaluate for malignancy. Radiologists can play a key role by conducting appropriate work-up and by raising awareness among both healthcare providers and the public about breast cancer risk assessment.