Cancer (Inflammatory breast cancer) in the breast; Lymph nodes and nodules in both lungs; Felt like relaxing of muscle under left arm; This spontaneous case was reported by a consumer and describes the occurrence of INFLAMMATORY CARCINOMA OF THE BREAST (Cancer (Inflammatory breast cancer) in the breast) and PULMONARY MASS (Lymph nodes and nodules in both lungs) in a female patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.   On 04-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 01-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In April 2021, the patient experienced MUSCLE DISCOMFORT (Felt like relaxing of muscle under left arm). On an unknown date, the patient experienced INFLAMMATORY CARCINOMA OF THE BREAST (Cancer (Inflammatory breast cancer) in the breast) (seriousness criterion medically significant) and PULMONARY MASS (Lymph nodes and nodules in both lungs) (seriousness criterion medically significant). The patient was treated with PACLITAXEL ALBUMIN (ABRAXANE) for Inflammatory breast cancer and Lung nodule, at a dose of 1 dosage form. At the time of the report, INFLAMMATORY CARCINOMA OF THE BREAST (Cancer (Inflammatory breast cancer) in the breast) and MUSCLE DISCOMFORT (Felt like relaxing of muscle under left arm) outcome was unknown and PULMONARY MASS (Lymph nodes and nodules in both lungs) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 19-Oct-2021, Positron emission tomogram: abnormal (abnormal) Showed an improvement in reduction of breast mass, and reduced amounts in both lymph nodes and nodules in the lungs.. On an unknown date, Laboratory test: abnormal (abnormal) Results showed that patient had cancer (Inflammentary Breast Cancer) in the breast, lymph nodes and nodules in both lungs..         Concomitant product use was not provided by the reporter. After administration of vaccines, withing 5-10 days, patient experienced what felt like a relaxing of muscles under her left arm and a mass fell into her left breast. Patient went to primary doctor who arranged for her to get various tests done and referred her to a hematology/oncology doctor. The result showed that patient had cancer (inflammatory breast cancer) in the breast, lymph nodes and nodules in both lungs. In June patient began chemotherapy (abraxane) treatment and when patient had a Petscan done on 19-Oct-2021, it showed an improvement in reduction of breast mass and reduced amount in both lymph nodes and nodules in the lungs. Patient continued abraxane. Patient also reported that the events worse after the booster shot.  Company Comment: This is a spontaneous case concerning a female of unknown age with no reported medical history who experienced the serious (medically significant), unexpected events of inflammatory breast cancer and pulmonary mass along the non-serious event of muscle discomfort 5 to 10 days after the second dose of RNA-1273. Testing was by unknown lab test that revealed the metastatic cancer and a PET scan that showed reduction of the masses after chemotherapy. Treatment was reported as abraxane and presumably it is continuing. The outcome is reported as ongoing. A confounder is that it is physiologically impossible for the metastatic cancer to have been caused by the vaccine in such a short time period. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   This case was linked to MOD-2022-508720 (Patient Link).; Sender's Comments: This is a spontaneous case concerning a female of unknown age with no reported medical history who experienced the serious (medically significant), unexpected events of inflammatory breast cancer and pulmonary mass along the non-serious event of muscle discomfort 5 to 10 days after the second dose of RNA-1273. Testing was by unknown lab test that revealed the metastatic cancer and a PET scan that showed reduction of the masses after chemotherapy. Treatment was reported as abraxane and presumably it is continuing. The outcome is reported as ongoing. A confounder is that it is physiologically impossible for the metastatic cancer to have been caused by the vaccine in such a short time period. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.