SHM Converge Scientific Abstract ePoster Gallery-Crab Without Myeloma: A Case of Refractory Hypercalcemia Unmasking HTLV-1 Associated Adult T-Cell Leukemia/Lymphoma

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This poster describes a case of <strong>HTLV-1–associated adult T-cell leukemia/lymphoma (ATLL)</strong> presenting as <strong>CRAB syndrome without myeloma</strong>. An <strong>83-year-old man</strong> with chronic kidney disease, diabetes, hypertension, and prior stroke developed <strong>somnolence and confusion</strong> after a recent <strong>levofloxacin</strong> exposure, along with <strong>fever, hypotension, diffuse morbilliform rash, and facial edema</strong>. Initial labs showed <strong>severe hypercalcemia (Ca 15.7)</strong>, <strong>worsening renal function (Cr 4.82)</strong>, and <strong>anemia (Hgb 7.9)</strong>, leading clinicians to first suspect <strong>drug hypersensitivity</strong> or <strong>plasma cell dyscrasia</strong>.

Despite the classic <strong>CRAB</strong> features often associated with multiple myeloma, the myeloma workup was negative and the hypercalcemia remained <strong>refractory</strong>. A key diagnostic clue came from the <strong>peripheral smear</strong>, which revealed <strong>cerebriform lymphocytes</strong>. Further testing, including <strong>HTLV-1 studies, flow cytometry, and skin biopsies</strong>, confirmed <strong>ATLL with cutaneous involvement</strong>.

The poster emphasizes several teaching points:  
- <strong>ATLL is an aggressive T-cell malignancy linked to HTLV-1</strong>, seen more commonly in the <strong>Caribbean, Japan, and West Africa</strong>.  
- It can <strong>mimic myeloma</strong>, especially when presenting with <strong>hypercalcemia, renal failure, anemia, and rash</strong>.  
- <strong>Anchoring bias</strong> can delay diagnosis when rash is attributed to a drug reaction or infection.  
- In patients with <strong>hypercalcemia, cytopenias, and rash</strong> but a <strong>negative myeloma evaluation</strong>, clinicians should <strong>review the peripheral smear</strong> and consider <strong>cutaneous T-cell malignancy/ATLL</strong> early.

Overall, the case highlights the importance of broad differential diagnosis and careful smear review in unexplained CRAB-like presentations.

Asset Subtitle

Manal Ahmidouch

Meta Tag

Author List Manal Ahmidouch, Manik Uppal, Nooshin Beygui, Rachel Sue

Category Clinical Vignettes

Concept Adult T-Cell Leukemia/Lymphoma

Concept HTLV-1

Concept Hypercalcemia

Concept Cerebriform Lymphocyte

Concept Cytopenia

Distinguished Non-Finalist

Presenter Organization Mount SInai Morningside/West

Presenting Author Manal Ahmidouch

Track Adult

Keywords

HTLV-1-associated ATLL

adult T-cell leukemia/lymphoma

CRAB syndrome

hypercalcemia

renal failure

anemia

cerebriform lymphocytes

cutaneous involvement

peripheral smear

anchoring bias

Adult T-Cell Leukemia/Lymphoma

HTLV-1

Hypercalcemia

Cerebriform Lymphocyte

Cytopenia