David Fajgenbaum, MD, MBA, MSc: Most Likely Diagnosis

Dr. David Fajgenbaum, Perelman School of Medicine, University of Pennsylvania, says the pathology of this patient is consistent with iMCD. Importantly, other disorders such as lymphoma, autoimmune disorders, and EBV-related lymphoproliferation were excluded. This patient has the plasmacytic variant of iMCD, which is the most frequent pathologic variant of MCD. Other pathologies, such as hyaline vascular variety and mixed cellularity (which has features of both plasmacytic and hyaline vascular variant), can also occur in iMCD. Both the negative LANA-1 stain and the absence of detectable replicating HHV-8 virus in the peripheral blood point to the idiopathic form of MCD.

What is the most likely diagnosis for this patient?

Guess the Diagnosis: Case 1

Lisa B. is a 47-year-old female store owner from St. Louis, with a 10-month history of fatigue, night sweats, and weight loss.

• She presents to her PCP with generalized lymphadenopathy, most prominent in the cervical region; there is no polyneuropathy, and patient does not report joint pain. She is referred to a hematologist to rule out lymphoma
• Medical history is unremarkable; family history relevant for a mother with systemic lupus erythematous and father who died with prostate cancer at 65 years old
• Her physical exam is notable for bilateral cervical lymphadenopathy (1-2 cm), mild splenomegaly, and mild edema
• Laboratory findings: anemia (Hgb 11 gm/dL), elevated CRP (35 mg/L) and ESR (80mm/hr), elevated platelets (400,000/mK), Igs (IgG: 4500 mg/dL, IgM: 1500 mg/dL, IgA: 300mg/dL)
• PET scan showed generalized lymphadenopathy with a maximum SUV of 4.5; FNA of the lymph node is uninformative; she was referred to a general surgeon for excisional lymph node biopsy

Lisa’s pathology report shows the following findings:

• Regressed germinal centers, scattered hyperplastic follicles, preserved architecture with patent peripheral sinuses and florid interfollicular plasmacytosis with no light chain restriction
• Prominent vascularization and hyalinization is present

In view of these findings, the hematologist orders further tests, which yield the following results:

• Lymph node: negative EBER, LANA-1, and IgG4 stains; negative PCR for B-cell clonality
• Additional laboratory work: negative ANA, negative dsDNA, anti-Smith and anti-phosholipid antibodies; monospot negative