Hepatosplenomegaly, first noted approximately 2 month(s) ago. The family noted abdominal pain, and he was evaluated by his primary care provider, who ordered CBC with differential, hemoglobin, platelet count, sedimentation rate (ESR) and CRP, EBV, CHEM 14, Monotest, Amylase, GGT, and Lipase as well as follow-up abdominal US and CT scan, CXR, and referral to GI.   He received his first dose of COVID-19 vaccination approximately 2 weeks before symptoms began. Severe abdominal pain at the onset in early Sept has resolved.    Other significant symptoms are periodic fevers, described by mom as "feeling warm" primarily in the evenings over the last few weeks with a range from 99.7-100.2 by thermometer over the last 4 days. Patient has been asymptomatic and feeling well during these temperatures. Other notable events include two minor cuts they reported became enlarged and infected, two minor non-traumatic nosebleeds roughly two weeks ago, and increased cough/congestion over the last week, notable as the patient received Prednisone 30mg from 11/4-11/10.  Parents state he always has had a difficult time "clearing infections" but no frequent skin infections or hospitalizations for major infections. They state that he saw an Allergy/Immunology provider as a child for his asthma and was found to have low vaccine titers and needed to get re-immunized.    Mother and Father and patient denied bleeding, dizziness, easy bruising, nausea, swollen lymph nodes, fever, chills, night sweats and vomiting. They state he has a history of taking a "long time to clear infection" such as viral infections. No severe infections or hospitalizations though. No fevers, chills, or night sweats.   In summary, Patient is a 17 y.o.  with Hepatosplenomegaly likely due to acute primary EBV infection.   Overall, symptoms and HSM began >8 weeks ago. Patient is doing well with no symptoms at this time. Liver and spleen still enlarged on US yesterday (11/23) but improving. Patient is cleared to return to activity/athletics, as splenic rupture due to EBV infection is quite rare after 4 weeks.    Previously healthy male with acute, severe abdominal pain approx 2 months ago (early Sept 2021).  Seen by PCP and workup was started. Imaging studies are as follows:  US Ab 9/21: Liver 16.9cm   Spleen 15.6cm CT Ab 9/22: Liver 19.6cm   Spleen 15.4cm US Ab 10.6: Liver 15.6cm   Spleen 15.2 cm US Ab 11/12: Liver N/A        Spleen 17.2cm US Ab 11/23: Liver 16.4cm  Spleen 15.2cm   His abdominal pain has resolved and overall he is feeling well.  Did receive COVID-19 vaccination approx 2 weeks before the symptoms began.  Has also had 2 cutaneous abscesses on his arms during this time, requiring expression of purulence and antibiotics.  He has had URI sx and sore throat for 2.5 weeks (started early Nov). Was given a course of corticosteroids from 11/4 to 11/10.  As of today (11/24) this URI symptoms have improved.  Parents state he has a history of "taking a long time to clear infection" such as viral infections. No severe infections or hospitalizations though. No fevers, chills, or night sweats.    Overall DDX for hepatosplenomegaly is broad and at this point Patient does not have any clear secondary symptoms to point to an etiology. At this time EBV infection appears to be most likely the sole cause.