Our patient is a 55-year-old woman of Chinese descent with no known medical history who initially presented to the office with chief complaints of painless swelling in the left side of the neck and a generalized rash persisting for the past 1 month. She is a lifetime non-smoker, has never abused alcohol, and has never used illicit drugs. No recent prescription or over-the-counter (OTC) drug or herbal supplement was used. Her only distant medical history was infectious mononucleosis at 24 years of age. She has a history of allergic reactions to cefaclor and reported developing an itchy rash. The patient reported to be healthy until she received her COVID-19 vaccine booster shot with Moderna's mRNA vaccination (mRNA-1273) against SARS-CoV-2 on the left arm. Prior vaccination history was uneventful. Approximately 4 days after the vaccination, she developed left arm pain and swelling at the site of injection. Approximately 1 week later, she developed swelling on the left side of the neck, and 2 weeks later, she developed a diffuse urticarial rash. She underwent a skin biopsy of a rash about a month later since presentation in the left mid-back that showed a perivascular cell infiltrate with eosinophils consistent with a drug reaction. Blood work performed on the same date showed a white blood cell (WBC) count of 2.5 x 109/L, a hemoglobin level of 10.9 g/L, and a platelet count of 296,000/mm3. Absolute lymphocyte count (ALC) was 1.79 x 109/L, absolute neutrophil count (ANC) was 0.54 x 109/L, MCV was 71 femtoliter, red blood cell (RBC) count was 5.04 x 109/L, and red cell distribution width (RDW) was 15.8%. Her comprehensive metabolic panel was within normal limits. Approximately 15 days later, after the biopsy, she developed a fever and mild cough and was tested positive for SARS-COV-19; however, her symptoms resolved completely within a few days. Repeat blood work done a month later since contracting COVID-19 was also consistent with bi-cytopenia with a hemoglobin level of 9.6 g/L and a WBC count of 1.8 x 109/L with ANC of 1.16 and ALC of 0.40 x 109/L. Liver transaminases were mildly elevated to alanine transaminase/aspartate transaminase (ALT/AST) of 49/59 units/L. Iron studies were within normal limits. Approximately 3 months later, after her COVID-19 infection, she presented again with a painless rash on her face, mainly in the nose and around the mouth and the chin, extending to the upper chest area. She reported worsening of her cervical lymphadenopathy and progressively worsening of lymphadenopathy in the neck, the axilla, and the groin and also developed a rash that progressed to involve the extremities and the back. She also described constitutional symptoms including fatigue and a weight loss of 4 kg over the last 3 months. She declined experiencing fever, chills, or significant night sweats. On physical examination, vitals were within normal limits except for tachycardia of 102 beats/min. Head and neck examination showed a patchy erythematous plaque-like rash on the face and around the nose, the perioral area, and the chin, extending to involve the upper chest and the arms. A patchy erythematous plaque-like rash was also observed in the back and the upper extremities, as shown in Figure 1. Lymph node examination showed diffuse adenopathy of the bilateral cervical area (levels I to V) more in the left than the right with a maximum size of 2 x 2 cm, palpable lymph nodes in bilateral axillae with a maximum size of 3 x 2 cm more in the left than in the right, and lymph nodes palpable in the bilateral inguinal area. Lymph nodes were soft in consistency and mildly tender. The rest of the examination was within normal limits. Further tests were performed, which showed a WBC count of 2.3 x 109/L (ANC of 1.66 x 109/L, ALC of 0.340 x 109/L, absolute monocyte count of 0.22 x 109/L, and absolute eosinophil count of 0.7 x 109/L), a hemoglobin level of 9 (MCV 75 femtoliter), and an erythrocyte sedimentation rate (ESR) of 46 mm. The chest x-ray was within normal limits. Cytomegalovirus (CMV) IgM and IgG antibodies were positive, Epstein-Barr virus (EBV) IgM antibody was negative, IgG was positive, the hepatitis panel (both B and C) was negative except Hep A IgG, which was positive, and rapid plasma reagin (RPR) was negative. Complement C3 was decreased to 49, and complement C4 was also decreased to 4 mg/dl, and total complement CH50 was <10 units/ml. ANA was positive, ANA titer was 1 to 320, and an ANA pattern of homogeneous and double-stranded DNA antibodies was negative. QuantiFERON TB was indeterminate. Histoplasma antibodies were negative, and toxoplasmosis IgG antibodies were negative. A computed tomography (CT) scan of the neck 1 month later showed extensive bilateral levels of 1-4 lymphadenopathy, the largest of which was the left base of neck level IV, which was approximately 3 x 2.7 x 2.0 cm. A CT scan of the chest with contrast showed bilateral axillary lymphadenopathy. The largest one on the right axilla was 2.6 x 1.2 cm. The largest one on the left axilla was 2.7 x 1.3 cm. There is no mediastinal or hilar lymphadenopathy. There is no pulmonary nodule or mass. She subsequently underwent a left supraclavicular lymph node biopsy. A supraclavicular lymph node biopsy showed atypical interfollicular B-cell proliferation associated with Rosai-Dorfman disease and a marked polyclonal plasmacytosis, as shown in Figure 2. Flow cytometry showed polyclonal B-cells, and T cells demonstrated no pan-T-cell antigen loss. Polymerase chain reaction (PCR) performed for Ig and T-cell receptor (TCR) gamma gene rearrangement showed a clonal rearrangement for Ig and a polyclonal pattern for TCR gamma.
Treatment was initiated with methylprednisolone at a dose of 24 mg a day, which was slowly tapered down over 3 weeks to 8 mg daily. The patient showed clinical improvements, her skin rash improved, and her lymphadenopathy clinically improved by 80%. She also reported improvements in fatigue and exercise tolerance and then continued on a slow taper of steroids over the next 3 weeks. After 2 months of taking steroids, the patient reported a complete resolution of her symptoms.