HEMATOMA; COULD NOT DECIPHER WORDS / LANGUAGE NOT FAMILIAR; BLEED ON LEFT TEMPORAL LOBE/ CEREBRAL HEMORRHAGE; BLOOD CLOT ON LEFT TEMPORAL LOBE; MIGRAINE; BLOOD CLOT ABOVE THE RIGHT KNEE; BLISTER ON FRONT OF LEFT LEG; RED INFLAMED ITCHY RASH ON FRONT OF LEFT LEG; EXTREMELY FATIGUE; This spontaneous report received from a patient concerned a 58 year old male.  The patient's height, and weight were not reported. The patient's concurrent conditions included non-alcohol user (abstains from alcohol), and non-smoker, and other pre-existing medical conditions included the patient unremarkable medical history, patient had no known drug allergies, did not have any drug abuse/illicit drug use, no prior vaccinations were received prior this vaccine, no prior reactions to any vaccinations, no family history of cancer, brain tumor, and aneurysm.  The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 1808978, expiry: 13-JUN-2021) dose was not reported, 01 total, administered on 02-APR-2021 at left deltoid for prophylactic vaccination. No concomitant medications were reported.  On 03-APR-2021, the patient experienced severe headache, extremely fatigue, right leg hurt after sitting too long. This got resolved without taking any medication. On 09-APR-2021, the patient experienced blood clot above the right knee, on same day patient had red inflamed rash with itch and blisters on front of left leg above the shin, on 15-APR-2021 patient has massage his primary physician to get steroid cream for rash. Patient had not come up in contact with new clothing or laundry detergent or outside exposures, or changes in diet, the rash did not get better even after using the steroid cream (triamcinolone), for about 3 days, but the cream actually seemed to increase the flare up. He stopped using the cream, and on unspecified date in MAY-2021 the rash eventually fully recovered on its own about 2 weeks after discontinuing the steroid cream (triamcinolone), patient had blisters but not with too much fluid in it. On (Sunday) 18-JUL-2021, the patient experienced thunderclap headache, worst headache which he had, and worst migraine ever, which was lasted for 10 minutes but did not get away. On following morning, 19-JUL-2021, he got up and while reading he could get few words out and lot of words could not decipher, as could not tell you what words were (language was not familiar with) or what they meant and that lasted for about an hour, also had brain fog. On Tuesday 22-JUL-2021 patient visited to doctor (primary care physician). On unspecified date patient went to ER (emergency room) with PCP (primary care physician) and had MRI (Magnetic resonance imaging) stat. Patient did not get in ER until 24-JUL-2021. On 24-JUL-2021, the patient was hospitalized and did MRI (Magnetic resonance imaging) and had bleed on left temporal lobe/ cerebral hemorrhage, Lab data MRI (Magnetic resonance imaging), (NR: not provided) Subacute m left temporal lobe Hemorrhage and hematoma. After admitting had treatment of heparin. There was no anything else. Later patient was transported to neuro ICU (intensive care unit) where did CT (computerized tomography) scan and with contrast with MRI had blood clot with left temporal lobe, Lab data CT (computerized tomography) scan (NR: not provided) Clot, no tumor or aneurysm. Patient had not paralysis, had some issue with deciphering words, but later became better now, could took and came up with right words, Treatment medications included: heparin. Physician could not say why this had happened, on unspecified date had all blood work was normal. Laboratory data included: CBC (complete blood count) (NR: not provided) Normal, also additionally different hematological test done and come up with nothing. Laboratory data (dates unspecified) included: Hematology test (NR: not provided) Normal. Additional discharge treatment medications (dates unspecified) included: apixaban (Eliquis) 5 mg, 1 tablet twice a day. Patient was ready to have discharge from hospital on 28-JUL-2021.The patient was hospitalized for 5 days. The Hematology/Oncology physician stated could not specify a reason as to why the patient had these clots, since the testing such as the angio-Cath did not find a brain tumor or aneurysm. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from blood clot above the right knee, blister on front of left leg, and red inflamed itchy rash on front of left leg on MAY-2021, and extremely fatigue on 04-APR-2021, and the outcome of bleed on left temporal lobe/ cerebral hemorrhage, blood clot on left temporal lobe, could not decipher words / language not familiar, hematoma and migraine was not reported. This report was serious (Hospitalization Caused / Prolonged).; Sender's Comments: V0- 20210758983 -Covid-19 vaccine ad26.cov2.S- Bleed on left temporal lobe/cerebral hemorrhage, Blood clot on left temporal lobe, blood clot above the right knee, Could nor decipher words/ language not familiar, Hematoma, Migraine . This event(s) is considered unassessable. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s).