She was very upset; invasive carcinoma in left breast and lymph nodes grade three; invasive carcinoma in left breast and lymph nodes grade three; This spontaneous case was reported by an other health care professional and describes the occurrence of INVASIVE BREAST CARCINOMA (invasive carcinoma in left breast and lymph nodes grade three) and METASTASES TO LYMPH NODES (invasive carcinoma in left breast and lymph nodes grade three) in a 45-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 047B21A and 019B21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Non-smoker.   On 25-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 22-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In August 2021, the patient experienced INVASIVE BREAST CARCINOMA (invasive carcinoma in left breast and lymph nodes grade three) (seriousness criteria medically significant and life threatening) and METASTASES TO LYMPH NODES (invasive carcinoma in left breast and lymph nodes grade three) (seriousness criteria medically significant and life threatening). On an unknown date, the patient experienced FEELING ABNORMAL (She was very upset). At the time of the report, INVASIVE BREAST CARCINOMA (invasive carcinoma in left breast and lymph nodes grade three), METASTASES TO LYMPH NODES (invasive carcinoma in left breast and lymph nodes grade three) and FEELING ABNORMAL (She was very upset) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In August 2021, Biopsy: invasive carcinoma in left breast and lymph nodes (abnormal) invasive carcinoma in left breast and lymph nodes grade three. On an unknown date, Mammogram: patient was fine (normal) patient was fine.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered INVASIVE BREAST CARCINOMA (invasive carcinoma in left breast and lymph nodes grade three) and METASTASES TO LYMPH NODES (invasive carcinoma in left breast and lymph nodes grade three) to be possibly related. No further causality assessment was provided for FEELING ABNORMAL (She was very upset).    No concomitant medication reported. No treatment information was provided.  The patient stated that after receiving both doses of the Moderna COVID 19 vaccine, she developed cancer four months later. She has no family history of breast cancer. She has a double negative breast cancer in her left breast, it came on fast and hard. She was extremely health conscious, non-smoker, regular exerciser (1hour a day) ; she exercises an hour a day and eats healthy. She believes that the vaccine has given her cancer. On Aug2021, she was diagnosed with an invasive carcinoma in left breast and lymph nodes grade three. The diagnosis was through a biopsy. The doctor said she needs chemotherapy, but she does not believe in chemotherapy. She stated that she was going to die at 45 because of "you people". She was very upset. She said a mammogram done three months prior and was fine, after getting the COVID 19 vaccine the she was diagnosed with cancer.  Company comment: This case concerns a 45-year-old, female patient with no relevant medical history, who experienced, serious unlisted event of invasive breast carcinoma and lymph node metastasis. The event occurred approximately 4 months after the second dose of Moderna COVID-19 Vaccine.  The rechallenge was not applicable as the event occurred after the second dose of Moderna COVID-19 Vaccine . Based on the pathophysiology of the event and mechanism of vaccine,  the events of breast carcinoma and lymph node metastasis may not be related to the Vaccine.  The benefit-risk relationship of Moderna COVID-19 Vaccine is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 11-Oct-2021: Follow up contains, Patient date of birth, vaccine dosage details and event details; Sender's Comments: This case concerns a 45-year-old, female patient with no relevant medical history, who experienced, serious unlisted event of invasive breast carcinoma and lymph node metastasis. The event occurred approximately 4 months after the second dose of Moderna COVID-19 Vaccine.  The rechallenge was not applicable as the event occurred after the second dose of Moderna COVID-19 Vaccine . Based on the pathophysiology of the event and mechanism of vaccine,  the events of breast carcinoma and lymph node metastasis may not be related to the Vaccine.  The benefit-risk relationship of Moderna COVID-19 Vaccine is not affected by this report.