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Difficulty: HardPathology and Biopsy Interpretation

A 26-year-old male is evaluated in the gastroenterology clinic for a 2-year history of non-bloody, foul-smelling diarrhea and an unintentional 7-kg (15.4-lb) weight loss. During this timeframe, he has required two courses of oral antibiotics for recurrent sinusitis and was hospitalized once for community-acquired pneumonia. His vital signs are within normal limits. Physical examination reveals a thin patient with mild temporal wasting.

Laboratory investigations show:
Hemoglobin: 10.4 g/dL
Mean corpuscular volume: 74 fL
Quantitative serum IgG: 210 mg/dL (Normal: 700-1600 mg/dL)
Quantitative serum IgA: <5 mg/dL (Normal: 70-400 mg/dL)
Quantitative serum IgM: 25 mg/dL (Normal: 40-230 mg/dL)
Anti-tissue transglutaminase IgA: Negative
Anti-deamidated gliadin peptide IgG: Negative

To establish a definitive diagnosis, an esophagogastroduodenoscopy is performed, which reveals scalloping of the duodenal folds. The corresponding histopathologic evaluation of the duodenal biopsies states:

"The mucosal architecture demonstrates severe villous blunting accompanied by crypt hyperplasia. There is a marked increase in intraepithelial lymphocytes (>40 per 100 enterocytes). The lamina propria contains a sparse inflammatory infiltrate characterized by an absolute absence of plasma cells. No granulomas, parasites, or foamy macrophages are identified."

Based on the clinical presentation and biopsy interpretation, which of the following is the most likely diagnosis?

  1. Common variable immunodeficiency enteropathyAnswer
  2. B
    Celiac disease
  3. C
    Giardiasis
  4. D
    Whipple disease
  5. E
    Tropical sprue

Answer

Common variable immunodeficiency enteropathy
The correct diagnosis is common variable immunodeficiency (CVID) enteropathy. The patient's clinical history of recurrent sinopulmonary infections combined with markedly decreased levels of IgG, IgA, and IgM establishes the diagnosis of CVID. Gastrointestinal involvement is common in CVID, often presenting as chronic diarrhea and malabsorption. While the duodenal biopsy in CVID enteropathy classically mimics celiac disease (exhibiting severe villous blunting, crypt hyperplasia, and intraepithelial lymphocytosis), the critical distinguishing histopathologic feature is the marked paucity or complete absence of plasma cells in the lamina propria. This reflects the underlying defect in B-cell differentiation and antibody production inherent to the disease.

Step-by-Step Solution

1
Analyze the clinical history and laboratory findings.
The patient has chronic diarrhea, weight loss, and recurrent sinopulmonary infections. Labs show pan-hypogammaglobulinemia (low IgG, IgA, and IgM).
To establish the underlying systemic disease, which is common variable immunodeficiency (CVID).
2
Evaluate the duodenal biopsy report.
The biopsy shows a celiac-like pattern (villous blunting, crypt hyperplasia, increased intraepithelial lymphocytes) but explicitly notes an absolute absence of plasma cells.
To differentiate between etiologies of villous blunting.
3
Synthesize clinical and histopathologic data to reach a final diagnosis.
The combination of CVID and a celiac-like enteropathy lacking plasma cells is diagnostic of CVID enteropathy.
To identify the specific gastrointestinal manifestation of the patient's immunodeficiency and avoid misdiagnosing seronegative celiac disease.

Key Concept

Common variable immunodeficiency (CVID) enteropathy can histologically mimic celiac disease with villous blunting and increased intraepithelial lymphocytes; however, it is uniquely distinguished by a profound paucity or complete absence of plasma cells in the lamina propria.
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Topics

Pathology and Biopsy Interpretation

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