Case Presentation: 69 year old female with a history of untreated hepatitis B presented with leg pain, fatigue, and a 13-pound unintended weight loss over 5 months. She had no family history of cancer and had unremarkable age-appropriate cancer screenings. On exam, she had normal vitals, bilateral paraspinal and hip tenderness and positive straight leg raises. Labs revealed calcium 14.1 mg/dL, creatinine 1.33 mg/dL, hemoglobin 10 gm/dL, and hepatitis B PCR 675,000 IU/mL. Lumbosacral spine x-ray showed new lytic lesions in the fifth lumbar spine and left iliac bone. The patient’s presentation was initially concerning for multiple myeloma, but labs showed a polyclonal pattern on serum protein electrophoresis with immunofixation. CT scans of the chest, abdomen, and pelvis demonstrated diffuse pulmonary nodules, intrathoracic lymph node enlargement, and numerous hepatic lesions consistent with metastatic carcinoma of unknown primary. Tumor markers showed an elevated CA 19-9 with normal CEA and AFP. A liver biopsy was performed given the patient’s history of untreated hepatitis B and extensive liver infiltrations, revealing moderately to poorly differentiated carcinoma that stained positive for pankeratin, CK7, mammaglobin, and CK19. Final pathology and imaging established a new diagnosis of Stage IV triple negative breast cancer in our patient without a palpable breast mass and who had a normal screening mammogram one month prior. Inpatient oncology was consulted to facilitate cancer workup and pain management. The patient was discharged home upon resolution of her hypercalcemia and followed up with outpatient oncology one week after discharge. Oncologists discussed chemotherapy, but in the context of the patient’s poor prognosis and functional status, she and her family decided to enroll in hospice.
Discussion: Breast cancer accounts for one third of incidental cancer diagnoses in women. While mammography is the gold standard screening modality, it misses 20-30% of breast cancers, most of which are interval breast cancers (IBC) diagnosed after a normal mammogram but before the next screening. Compared to screening-detected cancers, IBCs are six times more likely to be of higher grade and have 3.5 times the hazard for cancer-related mortality. A risk factor for IBCs is dense breast tissue, which our patient had. Dense breast tissue can reduce the sensitivity of mammograms to as low as 47%. Digital breast tomosynthesis is an alternative tool in women with dense breast tissue, as it has more than three times the cancer detection rate in this population compared to mammography. In metastatic breast cancer patients, there is a high prevalence of hypercalcemia (40%), anemia (41%), impaired kidney function (51%), and bony involvement (85%). While this constellation of findings is classic for multiple myeloma, it is important to evaluate for metastatic disease. In particular, breast cancer needs to be considered in female patients given its high incidence and limitations in screening.
Conclusions: Hospitalists should consider a broad differential when presented with signs and symptoms that may initially seem consistent with a certain malignancy. Involving Oncology early on and ensuring close outpatient follow up was key for this patient to expedite the diagnostic workup, assess her goals of care, and address her cancer-related pain. The collaborative effort between Hospitalists and Oncologists is essential to best navigate the complex care of a new cancer patient.