Hurricane Katrina evacuee develops a persistent rash

Diagnosis hinges on palpation and biopsy

To diagnose CTCL, you need to palpate for enlarged lymph nodes and perform a full-thickness punch biopsy of the lesion. If the biopsy is negative and the rash persists, take another biopsy—results can be falsely negative at the beginning stages of the disease.

There are no guidelines on which studies should be used for staging CTCL (TABLE), but some sources recommend that if lymph node involvement is suspected on physical exam, lymph node biopsies should be done in addition to a chest radiograph.³ In more advanced stages, consider a computed tomography (CT) scan of the abdomen and pelvis. A recent study concluded that CT and positron-emission tomography (PET) scans used together were more sensitive in staging, but this may not be cost-effective.⁴

Late-stage mycosis fungoides is usually associated with immunocompromise. Therefore, HIV testing should be performed in all patients with CTCL. Other important laboratory studies include complete blood count—with differential—as well as peripheral smear looking for Sézary cells, lactic dehydrogenase (LDH), liver function tests, and uric acid.

TABLE
Staging for cutaneous T-cell lymphoma based on the Tumor, Node, Metastasis (TNM) system