A 42-year-old woman, gravida 3 para 3, comes to the office due to left breast swelling and pain that have worsened over the past few weeks. The patient stopped breastfeeding her youngest child approximately 2 months ago. She developed left breast swelling and pain a month ago and was diagnosed with mastitis and prescribed a course of antibiotics. The patient completed the antibiotics and her symptoms initially improved, but she developed worsening symptoms again 2 weeks ago. She has type 2 diabetes mellitus for which she takes metformin but has no other chronic medical conditions. BMI is 46.6 kg/m2. Temperature is 37.6 C (99.7 F), blood pressure is 110/68 mm Hg, pulse is 88/min, and respirations are 18/min. The left breast is diffusely warm, erythematous, and has thickened skin dimpling. The right breast is normal. Which of the following is the most likely diagnosis for this patient?
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This patient's diffusely warm, erythematous breast with thickened skin dimpling is classic for inflammatory breast carcinoma (IBC). This rare, aggressive cancer is typically rapid in onset (eg, within months) and painful.
IBC can be clinically confused with an infectious process (eg, mastitis) due to the common symptoms of pain, erythema, and warmth. However, mastitis rapidly improves and resolves with antibiotics in most patients; therefore, patients who have limited or no improvement on antibiotic therapy require further evaluation for IBC or worsening infection (eg, breast abscess). Unlike breast abscess (which typically presents with a tender, fluctuant mass), IBC causes cutaneous edema, leading to a thickened peau d'orange appearance (eg, superficial skin dimpling, fine pitting) that is not usually seen with infection (Choices A and F).
Other possible signs and symptoms of IBC include itching, a palpable breast mass, and nipple changes (eg, flattening/retraction). Patients commonly have axillary lymphadenopathy that suggests metastatic disease, which is present in 20% of newly diagnosed patients (but not clinically evident in this patient). Evaluation includes mammography and ultrasound of the breast and axillary lymph nodes. Tissue biopsy is necessary to confirm the diagnosis.
(Choice B) Fat necrosis typically presents as an ill-defined, firm breast mass with irregular borders and a history of local breast trauma or surgery. Cutaneous findings may be absent or may manifest as localized ecchymosis, not diffuse erythema.
(Choices C and E) Infiltrating ductal carcinoma or lobular breast carcinoma may cause skin dimpling or breast contour changes. In contrast to IBC, these types of breast cancer do not cause diffuse breast erythema, edema, and a peau d'orange appearance.
Educational objective:
Patients with inflammatory breast carcinoma classically have symptoms of mastitis that do not improve (or only initially improve) with antibiotics. Features include diffuse breast erythema, pain, and edema with skin thickening and dimpling (peau d'orange appearance). Inflammatory breast carcinoma is a rapidly aggressive form of breast cancer, and many patients initially have metastatic disease.