Delayed radiographic diagnosis of distal femoral metastases in breast cancer: A case report from Cocody University Teaching Hospital (Côte d’ivoire)

Abstract

Bone metastases represent a frequent complication of breast cancer, affecting more than one third of patients. Delayed investigation of persistent focal bone pain in a breast cancer patient can lead to serious consequences. We report a case of delayed radiographic diagnosis of distal femur metastases in a breast cancer patient, where the initial standard X-ray was normal. The diagnosis of bone metastasis was established by a second X-ray 11 months later, following disease progression. This case highlights the limitations of conventional radiography and highlights the importance of using PET-CT, MRI, or bone scintigraphy imaging modalities methods for early detection of metastatic lesions to guide therapeutic management.

Introduction

Bone metastasis is a secondary spread of cancer to the bone. Breast cancer is the most common osteolytic cancer [1]. It causes osteolytic lesions frequently located in the spine and pelvis [2]. Long bone involvement is less common [2]. Conventional X-ray imaging appears to have limitations in the early diagnosis of these bone metastases. We report a case of delayed radiographic diagnosis of a distal femoral metastasis secondary to breast cancer.

Case presentation

A 44-year-old female patient presenting with cT2N0M0 invasive ductal carcinoma of the left breast, estrogen receptor (ER) = 100%, progesterone receptor (PR) = 98%, HER2 status = 0, diagnosed in June 2022, who underwent a left partial mastectomy in October 2022, followed by 8 sessions of chemotherapy, 35 sessions of radiotherapy, and tamoxifen-based hormone therapy, resulting in the complete disappearance of the nodule. The patient was monitored regularly every 3 months until February 2024, when a follow-up ultrasound and mammogram revealed the reappearance of a left breast nodule with axillary lymphadenopathy. A total mastectomy and axillary lymph node dissection were performed in October 2024. The surgical specimen showed, on immunohistochemical analysis, a non-specific invasive ductal carcinoma of the left breast, Nottingham grade II, Ellis and Elston score 6, cT2N1M0, Ro = 0, Rp = 0, HER2 = 0. The patient resumed radiotherapy sessions, which she attended regularly until November 2024, when she presented with mechanical pain in her right knee associated with swelling without local signs of inflammation. This pain became inflammatory and debilitating one month prior to her admission to our department in February 2026.

This clinical picture developed in an afebrile context associated with unquantifiable weight loss, vomiting and constipation.

Physical examination revealed a flexed right knee with a painful swelling extending to the lower third of the thigh, without local signs of inflammation or collateral venous circulation.

At the level of the skull, there was a swelling of approximately 3 cm, immobile, non-tender, of semi-soft consistency.

At the level of the spine, no pain was noted on palpation of the dorsal and lumbar spinous processes.

In terms of diagnostic investigations, an initial conventional X-ray performed in May 2025 was normal (Fig. 1). A second conventional X-ray of the right knee, taken four months later, revealed osteolysis of the distal end of the right femur (Fig. 2).

Fig. 1.

Normal appearance on a conventional X-rays of the right knee, lateral view (A) and anterioposterior view (B), at the start.

Fig. 2.

Conventional X-ray of the right knee taken 4 months after the first, showing the right knee In the lateral view (A) and anterioposterior view (B), revealing osteolytic lesions of the distal right femur.

X-rays of the skull revealed oval-shaped defects with osteolytic lesions of the skull (Fig. 3).

Fig. 3.

Conventional X-ray of the skull anterioposterior view (A) and lateral view (B), showing oval-shaped lacunae of varying sizes with lysis of the skull.

The CT scan of the right knee revealed osteolysis with osseous fragmentation of the distal right femur (Fig. 4).

Fig. 4.

CT scan of the right knee, sagittal section (A) and 3D reconstruction (B) showing osteolytic lesions of the distal right femur with a pathological fracture.

The CT scan of the thoracic and lumbar spine in sagittal and coronal sections (Fig. 5) and 3D reconstruction (Fig. 6) showed osteolytic lesions at various stages in the thoracic and lumbar spine, as well as in the costal and iliosacral regions.

Fig. 5.

CT scan of the thoracic and lumbar spine, showing sagittal (A) and coronal (B) sections with osteolytic lesions at various stages in the thoracic and lumbar spine, as well as in the costal and iliosacral regions.

Fig. 6.

3D reconstruction of a CT scan of the thoracic and lumbar spine, showing anterior (A) and posterior (B) views, revealing multifocal osteolytic lesions.

Biological assessment revealed severe hypochromic microcytic anemia at 5 g/dL, hypercalcemia at 137.4 mg/L, serum albumin = 42 g/L, corrected serum calcium = 135.3 mg/L, urea = 0.23 g/L, and serum creatinine = 12.6 mg/L.

In view of the osteolytic lesions in the skull, ribs and pelvis, the possibility of multiple myeloma was raised. Serum protein electrophoresis done did not reveal any monoclonal peak. The bone myelogram was normal.

A bone biopsy could not be performed

A diagnosis of bone metastases from breast cancer was established following the third biopsy of the left breast, with immunohistochemistry revealing a non-specific invasive carcinoma classified as T4N10M1, estrogen receptors = 100%, progesterone receptors = 98%, HER2 receptors = 0.

The management consisted of a knee immobilization brace, surgical referral for prosthetic fitting, and oral morphine-based analgesics.

Given the clinical emergency with respect to severe anemia and malignant hypercalcemia, an isogroup and iso-Rhesus compatible blood transfusion, rehydration, and intravenous bisphosphonates were administered.

Evolution while on treatment was marked by the sudden onset respiratory distress, associated with a fever of 39°C and impaired consciousness.

Investigations revealed severe sepsis of pulmonary origin.

The patient died on the seventh day of probabilistic dual antibiotic therapy.

Discussion

Bone metastases complicate approximately 40 per cent of breast cancers cases [3]. They most commonly occur within 5 years of treatment for the breast tumor [4,5]. Although our patient was under regular follow-up, she developed bone metastases 3 years after the tumor was diagnosed. The presenting symptom was knee pain, initially of mechanical origin, with slight swelling suggestive of a degenerative process. Neoplastic bone pain is insidious in onset, deep-seated, constant, intense, inflammatory, resistant to conventional analgesics and requires the use of opioid analgesics. In our patient, the pain became inflammatory one month prior admission in the hospital, necessitating the use of morphine. The initial standard X-ray of the knee, performed seven months after the onset of symptoms, had failed to detect any bone lesions. Radiological abnormalities were observed 11 months after the onset of symptoms. The lesions found consisted of osteolysis of the distal right femur. A conventional X-ray remains the first diagnostic test requested in a cancer patient [6]. Its sensitivity remains low. Indeed, 30 to 50 per cent of the bone matrix must be destroyed before radiological signs appear [7,8]. Thus, a normal X-ray does not rule out bone metastasis. Bone scintigraphy, on the other hand, can identify lesions as small as 2 millimeters 18 months earlier. Once it has been determined that the lesion is potentially malignant, a whole-body bone scan must be performed to identify other affected sites [7,8]. A bone scan had not been performed on our patient.

In addition to the knee, radiographic lesions resembling lacunae of varying sizes and lysis were noted in the skull. These abnormalities had raised suspicion of multiple myeloma. The myelogram performed was normal. A diagnosis of bone metastases was made in view of the signs of progressive breast cancer. Bone metastases from breast cancer can occur in the skeletal structure of the trunk, the skull and the humerus. This is thought to be because tumor cells travel retrograde via the mammary veins and rapidly reach these areas. The axial skeleton is frequently affected due to its highly vascularized red bone marrow [9]. According to the literature, the femur is the most common peripheral site, particularly its proximal end, which is more fragile and exposed to mechanical stress [10,11]. Involvement of the distal end, although less common, could be explained by the very high vascularization of this area above the knee. In the absence of a PET scan, which was unavailable in our practice, thoracic-abdominal-pelvic computed tomography (CT) enabled the detection of multi-focal osteolytic lesions. It revealed destruction of the cortical bone with crumbling of the distal femur. CT is the method of choice for assessing cortical destruction and juxta-articular metastases [12]. Osteolytic metastases are frequently complicated by hypercalcemia [11]. Undiagnosed hypercalcemia can lead to significant morbidity and may result in sudden death due to cardiac arrhythmia. Our patient presented with malignant hypercalcemia accompanied by uncontrollable vomiting, without any cardiac arrhythmia.

Conclusion

This case highlights the delayed diagnosis of bone metastases on standard X-rays. It emphasizes on the importance of using a PET scan, MRI or bone scan in the presence of any persistent focal bone pain in a patient with breast cancer, to enable early diagnosis.

Authors contributions

Coulibaly Yaya (literature review, manuscript writing), Hodonou Fourrier, Kollo Nzima Kevin, (English translation), Meité Novanly, Goua Jean Jacques (observation writing), Kpami You Nina Carmelle, Bamba Aboubakar, Coulibaly Abidou Kawélé (manuscript correction).

Patient consent

Informed consent was obtained from the patient's parents for the publication of this case, as the patient was unconscious.