Dermatology MCQ - Viral Infections - HTLV-1 Infection

A 45-year-old woman from Jamaica presents with progressive spastic paraparesis, urinary incontinence, and constipation. Neurologic examination reveals hyperreflexia in the lower extremities and a spastic gait. Laboratory studies show atypical lymphocytes with "flower cells" on peripheral smear and a positive serology for human T-lymphotropic virus type 1 (HTLV-1). Which of the following is the most likely associated hematologic disorder in this patient?

A) Chronic lymphocytic leukemia
B) Adult T-cell leukemia/lymphoma
C) Hairy cell leukemia
D) Hodgkin lymphoma
E) Multiple myeloma

Correct Answer: B) Adult T-cell leukemia/lymphoma

Explanation

This patient presents with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic neurological disease, and is at risk for a specific hematologic malignancy due to the same viral infection.

Key Features of HTLV-1 Infection:

• Neurological Disease (HAM/TSP):

  • Progressive spastic paraparesis (weakness and spasticity of lower limbs).

  • Urinary incontinence and constipation due to autonomic involvement.

  • Hyperreflexia, Babinski sign, and sensory disturbances.

• Hematologic Disease:

  • Adult T-cell leukemia/lymphoma (ATLL) is the classic malignancy associated with HTLV-1.

  • "Flower cells" on peripheral smear are pathognomonic for ATLL—atypical lymphocytes with convoluted, lobulated nuclei.

• Epidemiology: Endemic in Caribbean, Japan, and parts of Africa. Transmission occurs via breastfeeding, sexual contact, or blood transfusion.

Why ATLL is the Answer:

• HTLV-1 is directly oncogenic; its Tax and HBZ proteins drive T-cell proliferation and inhibit apoptosis, leading to ATLL.

• ATLL has four subtypes: acute, lymphoma, chronic, and smoldering. The acute and lymphoma subtypes are aggressive.

• Skin manifestations in ATLL include nodules, plaques, or erythroderma, often with histology resembling mycosis fungoides.

Why Not the Other Options?

• (A) Chronic lymphocytic leukemia (CLL): A B-cell malignancy (CD5+/CD19+), not associated with HTLV-1.

• (C) Hairy cell leukemia: A B-cell leukemia with "hairy" projections, associated with BRAF mutations, not HTLV-1.

• (D) Hodgkin lymphoma: Characterized by Reed-Sternberg cells; linked to EBV, not HTLV-1.

• (E) Multiple myeloma: A plasma cell disorder, not T-cell associated.

Management:

• HAM/TSP: Corticosteroids, interferon-α, or physical therapy may slow progression.

• ATLL: Aggressive chemotherapy followed by allogeneic stem cell transplant for eligible patients.

Prognosis:

• HAM/TSP is progressive and disabling.

• ATLL has a poor prognosis (median survival <1 year for acute subtype).

Note: HTLV-1 can also cause infective dermatitis (chronic eczema in children) and uveitis. Screening is crucial in endemic areas.