cyst in right breast; loss of appetite; Pain; stomach upset; Diarrhea; Fatigue; muscle pain in back; low iron; thyroid issues following covid vaccine; lost eight pound; This spontaneous case was reported by a consumer and describes the occurrence of BREAST CYST (cyst in right breast) in a 62-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product ADALIMUMAB (HUMIRA) for Hidradenitis suppurativa.    The patient's past medical history included Surgery (to remove cyst in right breast). Concurrent medical conditions included Diabetes and Hidradenitis suppurativa (moderate to severe).   In April 2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 05-May-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date, the patient started ADALIMUMAB (HUMIRA) (Subcutaneous) at an unspecified dose. On an unknown date, ADALIMUMAB (HUMIRA) (Subcutaneous) dosage was changed to at an unspecified dose. In May 2021, the patient experienced THYROID DISORDER (thyroid issues following covid vaccine) and WEIGHT DECREASED (lost eight pound). In June 2021, the patient experienced BLOOD IRON DECREASED (low iron). On an unknown date, the patient experienced BREAST CYST (cyst in right breast) (seriousness criterion medically significant), DECREASED APPETITE (loss of appetite), PAIN (Pain), ABDOMINAL DISCOMFORT (stomach upset), DIARRHOEA (Diarrhea), FATIGUE (Fatigue) and MYALGIA (muscle pain in back). At the time of the report, BREAST CYST (cyst in right breast), THYROID DISORDER (thyroid issues following covid vaccine), WEIGHT DECREASED (lost eight pound), DECREASED APPETITE (loss of appetite) and BLOOD IRON DECREASED (low iron) outcome was unknown and PAIN (Pain), ABDOMINAL DISCOMFORT (stomach upset), DIARRHOEA (Diarrhea), FATIGUE (Fatigue) and MYALGIA (muscle pain in back) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In May 2021, Weight decreased: lost eight pound. On 21-Jun-2021, Laboratory test: Low iron.         No concomitant medications were reported.  The patient had loss of appetite for about two days after injecting.  It was unknown if patient was enrolled in a COVID-19 vaccine trial.  The reporter causality for the events of cyst in right breast, fatigue, thyroid issues following covid vaccine, lost eight-pound, loss of appetite, low iron, pain, muscle pain in back, diarrhea and stomach upset with HUMIRA(Solution for injection in pre-filled pen) was not provided.  No treatment medications were reported.  This case was identified as part of a retrospective clean-up activity where certain emails received in the Moderna mailbox were missed to be booked in.  Company Comment: This spontaneous case concerns a 62-year-old, female patient with concurrent conditions of hidradenitis suppurativa treated with adalimumab and diabetes, who experienced an unexpected, medically significant event of Breast cyst, right in association with a dose of mRNA-1273 vaccine. Exact onset latency of the event relative to vaccination cannot be determined with an unknown event's onset date. Patient received a 2-dose primary series of mRNA-1273 vaccine at approximately 1 month apart. Reportedly, patient had thyroid issues and lost 8 pounds the following month after receiving a 1st dose of mRNA-1273 vaccine. On an unknown date, patient underwent removal of her breast cyst, right and had loss of appetite for about 2 days. Diagnostics included a low iron level after 47 days upon receiving a 2nd dose of mRNA-1273 vaccine. Further details on the medical history, clinical course, diagnostics, and treatments were not reported. Patient's underlying conditions and treatment with adalimumab remain as confounders in this case. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement.; Sender's Comments: This spontaneous case concerns a 62-year-old, female patient with concurrent conditions of hidradenitis suppurativa treated with adalimumab and diabetes, who experienced an unexpected, medically significant event of Breast cyst, right in association with a dose of mRNA-1273 vaccine. Exact onset latency of the event relative to vaccination cannot be determined with an unknown event's onset date. Patient received a 2-dose primary series of mRNA-1273 vaccine at approximately 1 month apart. Reportedly, patient had thyroid issues and lost 8 pounds the following month after receiving a 1st dose of mRNA-1273 vaccine. On an unknown date, patient underwent removal of her breast cyst, right and had loss of appetite for about 2 days. Diagnostics included a low iron level after 47 days upon receiving a 2nd dose of mRNA-1273 vaccine. Further details on the medical history, clinical course, diagnostics, and treatments were not reported. Patient's underlying conditions and treatment with adalimumab remain as confounders in this case. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement.