Hip Mass: Breast Carcinoma

By Aimun Shabbir¹, Asif Husain Osmani²

Affiliations

1. Department of Medicine, Dr. Ziauddin Hospital and University, Karachi, Pakistan
2. Department of Oncology, Dr. Ziauddin Hospital and University, Karachi, Pakistan

doi: 10.29271/jcpsp.2026.08.1099

Sir,

A 45-year premenopausal female patient with no family history of cancer presented with difficulty walking and pro- gressive pain in her left hip for three months. She was in a wheelchair with a pain scale of 8 in the left hip and an ECOG status of PS-3. An MRI scan of the left hip revealed a large expansile bony lesion involving the left acetabulum, ischium, and inferior pubic ramus, with periosseous soft-tissue exten- sion. Hip mass biopsy samples revealed metastatic deposits of adenocarcinoma of breast origin. Furthermore, an FDG PET/CT scan revealed a large FDG-avid destructive osteolytic lesion with an internal soft tissue component involving the left acetabulum, left ischium, and left inferior pubic ramus, with a SUV value of 19.4. Another FDG-avid osteolytic lesion was identified in the left iliac bone, with a SUV of 8.8. A hyper- metabolic osteolytic lesion was also identified in the manu-brium sterni, having an SUV of 8.1. An ill-defined area of asymmetrical parenchymal density with overlying dermal retraction was identified involving the upper outer quadrant of the right breast. It measured approximately 2.1×1.3 cm, with a SUV ranging up to 3.2 (Figure 1). US-guided biopsy of the right breast lesion revealed grade 2 invasive breast carcinoma; oestrogen receptor (ER), 90% positive; progesterone receptor (PR), 90% positive; HER2/neu negative; and a Ki-67 index of 5–10%. Germline BRCA1 and BRCA2 were wild-type.

Figure 1: (Baseline PET scan): An ill-defined area of asymmetrical paren-chymal density in the right breast (21 x 13 mm) with an SUVmax of 3.2. FDG avidity of hypermetabolic osteolytic deposits, with appearance of sclerosis,  involving the left acetabulum, left ischium, and left inferior pubic ramus, with an SUVmax of 19.4; the left iliac bone, with an SUVmax of 8.4; and the left side of  the  manubrium  sterni,  with  an  SUVmax  of  8.1.

She received palliative radiotherapy to the hip lesion (30 Gy in 5 fractions). Subsequently, she was treated with systemic therapy, consisting of ribociclib 600 mg on Days 1 to 21 once monthly, with letrozole 2.5 mg once daily. Goserlin 3.6 mg subscutaneous every 28 days and zoledronic acid 4 mg once every three months. She was assessed with an ECG and blood tests as per guidelines. Pain intensity decreased over time, and she started walking with support. After three months, an FDG PET/CT scan demonstrated a partial metabolic response (PMR) in the primary breast lesion (12 x 14 mm vs. 21 x 13 mm and SUVmax of 2.4 vs. 3.2; >30%). A significant interval reduction in the FDG avidity of the hypermetabolic osteolytic deposits, with the appearance of sclerosis, was noted in the left acetabulum, left ischium, and left inferior pubic ramus, with a decrease in SUVmax from 19.4 to 6.7; the left iliac bone, with a decrease in SUVmax from 8.4 to 1.4; and the left manubrium sterni, with a decrease in SUVmax from 8.1 to 2.9 (Table I). She continued on the same treatment regimen with no adverse events. PET scan after 6 months showed further improvement (Table I). After 9 months, she had overall metabolic complete response. Therefore, she will continue on the same treatment until progression of disease or grade 3 or 4 adverse effects.

Table  I:  Response  evaluation  (PET/CT  scan).

Body parts	Baseline	After 3 months	After 6 months
Left acetabulum, left ischium, and left inferior pubic ramus	SUV 19.4.	SUV 6.7	SUV 3.7
Left iliac bone	SUV 8.4	SUV 2.3	Non-avid – SUV 1.4
Manubrium sterni	SUV 8.1	SUV 2.9	SUV 3.1
Right breast	SUV 3.2 (2.1 x 1.3 cm)	SUV 2.4 (1.2 x 1.4 cm)	SUV 2.3 (1.2 x 1.4 cm)

Metastatic lesions in the hip roughly account for 10%, with the highest frequency from breast cancer.¹ MRI and FDG-PET/CT have high and comparable accuracy in diagnosing bone meta- stases in breast cancer and outperform bone scintigraphy and CT scan regarding sensitivity.² FDG-PET/CT for response evaluation is more sensitive in detecting disease status as com- pared to CT and bone scintigraphy.³

Ribociclib (CDK4/6 inhibitor) and letrozole, a dual blockade supported by the MONALEESA-2 trial, play a crucial role in controlling disease progression. Ribociclib directly inhibits cell-cycle progression, thereby suppressing tumour growth at both the primary site and metastatic skeletal lesions.⁴ Ribociclib plus letrozole combination after median follow-up of 6.6 years showed a significant overall survival benefit of 63.9 months (95% confidence interval [CI], 52.4 to 71.0) as com- pared to placebo plus letrozole with 51.4 months (95% CI, 47.2 to 59.7, hazard ratio for death, 0.76; 95% CI, 0.63 to 0.93; two-sided p = 0.008).⁵ For bone metastases due to breast cancer, the use of zoledronic acid every 12 weeks compared with the standard dosing interval of every 4 weeks remained non-inferior  in  terms  of  skeletal  events.⁵

COMPETING INTEREST:
The  authors  declared  no  conflict  of  interest.

AUTHORS’ CONTRIBUTIONS:
AS:  Literature  search  and  manuscript  writing.
AHO: Literature search, manuscript writing, and overall supervision.
Both authors approved the final version of the manuscript to be published.

REFERENCES

1. Horowitz SM, Berman AT. Metastatic Disease of the Hip. In: Bono JV, McCarthy JC, Thornhill TS, Bierbaum BE, Turner RH, Eds. Revision Total Hip Arthroplasty. Springer, New York, NY; 1999. pp.498-504. doi: 10.1007/978-1-4612-1406-9_65.
2. Gerke O, Naghavi-Behzad M, Nygaard ST, Sigaroudi VR, Vogsen M, Vach W, et al. Diagnosing bone metastases in breast cancer: A systematic review and network meta-analysis on diagnostic test accuracy studies of 2-[¹⁸F]FDG-PET/CT, ¹⁸F-NaF-PET/CT, MRI, contrast-enhanced CT, and bone scintigraphy. Semin Nucl Med 2025; 55(1):137-51. doi: 10.1053/j.semnuclmed.2024.10.008.
3. Hildebrandt MG, Naghavi-Behzad M, Vogsen M. A role of FDG-PET/CT for response evaluation in metastatic breast cancer? Semin Nucl Med 2022; 52(5):520-30. doi: 10. 1053/j.semnuclmed.2022.03.004.
4. Hortobagyi GN, Stemmer SM, Burris HA, Yap YS, Sonke GS, Hart L, et al. Overall survival with ribociclib plus letrozole in advanced breast cancer. N Engl J Med 2022; 386(10): 942-50. doi: 10. 1056/NEJMoa2114663.
5. Himelstein AL, Foster JC, Khatcheressian JL, Roberts JD, Seisler DK, Novotny PJ, et al. Effect of longer-interval vs. standard dosing of zoledronic acid on skeletal events in patients with bone metastases: A randomized clinical trial. JAMA 2017; 317(1):48-58. doi: 10.1001/jama.2016. 19425.