Bilateral Upper Arm Granulomas Induced by Leuprorelin Acetate Injection Mimicking Malignant Soft Tissue Tumors: A Case Report

Leuprorelin acetate is a common anticancer medication used for prostate cancer treatment. One of the local adverse reactions after leuprorelin injection is the development of reactive granulomas, typically presenting as subcutaneous nodules. In this case report, we describe a 73-year-old patient with prostate cancer who developed unusually large sized intramuscular reactive granulomas, which mimicked malignant soft tissue tumors. The patient, who had been receiving leuprorelin acetate treatment for the past 12 months, noticed painful masses in both upper arms. Based on the findings of magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography/computed tomography, a diagnosis of malignant soft tissue tumor was strongly suggested. However, further investigation through needle biopsy ultimately led us to the final diagnosis of reactive granuloma. The masses spontaneously resolved after discontinuation of leuprorelin injection. While reactive granulomas after leuprorelin injections are not rare, intramuscular cases are relatively uncommon. Despite using imaging studies as a rational initial approach in the diagnostic process, as we did in our case, their results turned out to be indistinguishable from those of malignant soft tissue tumors, thus highlighting the importance of pathological examination in confirming diagnosis, especially when a patient presents with atypical clinical manifestations

Depletion of R270C Mutant p53 in Osteosarcoma Attenuates Cell Growth but Does Not Prevent Invasion and Metastasis In Vivo

Novel therapeutic targets are needed to better treat osteosarcoma, which is the most common bone malignancy. We previously developed mouse osteosarcoma cells, designated AX (accelerated bone formation) cells from bone marrow stromal cells. AX cells harbor both wild-type and mutant forms of p53 (R270C in the DNA-binding domain, which is equivalent to human R273C). In this study, we showed that mutant p53 did not suppress the transcriptional activation function of wild-type p53 in AX cells. Notably, AXT cells, which are cells derived from tumors originating from AX cells, lost wild-type p53 expression, were devoid of the intact transcription activation function, and were resistant to doxorubicin. ChIP-seq analyses revealed that this mutant form of p53 bound to chromatin in the vicinity of the transcription start sites of various genes but exhibited a different binding profile from wild-type p53. The knockout of mutant p53 in AX and AXT cells by CRISPR–Cas9 attenuated tumor growth but did not affect the invasion of these cells. In addition, depletion of mutant p53 did not prevent metastasis in vivo. Therefore, the therapeutic potency targeting R270C (equivalent to human R273C) mutant p53 is limited in osteosarcoma. However, considering the heterogeneous nature of osteosarcoma, it is important to further evaluate the biological and clinical significance of mutant p53 in various cases