She experienced inflammation of subcutaneous tissue in her right leg below the right knee and below the joint anteriorly over the tibial plateau./similar area has appeared distally down the right leg not in the same location as the first.; Legs were hurting as if she had restless leg syndrome; She could not get out of bed; Noticed a large soft knot inside her leg above the knee/tearing feeling in her leg and developed another knot above the first one; Sore arm/shooting pains in the front of her; Limping around and stuff due to the pain; Not immunocompromised; Blood clot; Area was experiencing swelling and tenderness in a 1 inch diameter.; Area was experiencing swelling and tenderness in a 1 inch diameter.; This spontaneous case was reported by a physician and describes the occurrence of INFLAMMATION (She experienced inflammation of subcutaneous tissue in her right leg below the right knee and below the joint anteriorly over the tibial plateau./similar area has appeared distally down the right leg not in the same location as the first.), RESTLESS LEGS SYNDROME (Legs were hurting as if she had restless leg syndrome), MOBILITY DECREASED (She could not get out of bed), LIMB MASS (Noticed a large soft knot inside her leg above the knee/tearing feeling in her leg and developed another knot above the first one) and PAIN IN EXTREMITY (Sore arm/shooting pains in the front of her) in a 62-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 039B21A and 046A21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included COVID-19 (last march or April of last year).   On 26-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 26-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 19-Aug-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 18-Aug-2021, the patient experienced SWELLING (Area was experiencing swelling and tenderness in a 1 inch diameter.) and TENDERNESS (Area was experiencing swelling and tenderness in a 1 inch diameter.). On 22-Aug-2021, the patient experienced THROMBOSIS (Blood clot). On an unknown date, the patient experienced INFLAMMATION (She experienced inflammation of subcutaneous tissue in her right leg below the right knee and below the joint anteriorly over the tibial plateau./similar area has appeared distally down the right leg not in the same location as the first.). an unknown date, the patient experienced RESTLESS LEGS SYNDROME (Legs were hurting as if she had restless leg syndrome), MOBILITY DECREASED (She could not get out of bed), LIMB MASS (Noticed a large soft knot inside her leg above the knee/tearing feeling in her leg and developed another knot above the first one), PAIN IN EXTREMITY (Sore arm/shooting pains in the front of her), GAIT DISTURBANCE (Limping around and stuff due to the pain) and OFF LABEL USE (Not immunocompromised). The patient was treated with BETAMETHASONE (CELESTONE [BETAMETHASONE]) for Swelling, at a dose of 1 UNK; TRAMADOL for Adverse event, at an unspecified dose and frequency; PARACETAMOL (TYLENOL) for Adverse event, at an unspecified dose and frequency; IBUPROFEN (ADVIL [IBUPROFEN]) for Adverse event, at an unspecified dose and frequency; CORTISONE for Adverse event, at an unspecified dose and frequency and MELOXICAM for Adverse event, at a dose of 15 mg. On 23-Aug-2021, INFLAMMATION (She experienced inflammation of subcutaneous tissue in her right leg below the right knee and below the joint anteriorly over the tibial plateau./similar area has appeared distally down the right leg not in the same location as the first.), SWELLING (Area was experiencing swelling and tenderness in a 1 inch diameter.), TENDERNESS (Area was experiencing swelling and tenderness in a 1 inch diameter.) and GAIT DISTURBANCE (Limping around and stuff due to the pain) had resolved. At the time of the report, RESTLESS LEGS SYNDROME (Legs were hurting as if she had restless leg syndrome), MOBILITY DECREASED (She could not get out of bed), LIMB MASS (Noticed a large soft knot inside her leg above the knee/tearing feeling in her leg and developed another knot above the first one), PAIN IN EXTREMITY (Sore arm/shooting pains in the front of her) and THROMBOSIS (Blood clot) outcome was unknown and OFF LABEL USE (Not immunocompromised) had resolved.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   No concomitant product information was provided.  Additional information reported include that the patient had a large soft knot inside the legs, above the knees and close to tibia which the physician ruled out as blood clot.   This case was linked to MOD-2021-295607, MOD-2021-295596 (Patient Link).   Most recent FOLLOW-UP information incorporated above includes: On 24-Aug-2021: New events, treatment drugs, suspect product details and new reporter details were added.