Cryptococcal mesenteric lymphadenitis in an immunocompromised host.

Sir,

Cryptococcal infection is one of the most common life-threatening diseases seen more commonly in patients with acquired immunodeficiency syndrome (AIDS) and in transplant patients on immunosuppressive agents or other forms of immunosuppression. The infection starts in the respiratory tract but secondarily involves the central nervous system, lungs, skin, lymph nodes, bone marrow, gastrointestinal tract, retina, liver, spleen, and other parts of the body.[1] Most cryptococcal infections present as meningoencephatlitis, followed by pulmonary and skin infection. However, even in disseminated cryptococcosis, lymph nodes are usually spared. In addition, selective involvement of lymph nodes, so called “lymphonodular cryptococcosis,” is a rare entity and was reported more frequently in children.[2] Although there have been several reported cases of cryptococcal lymphadenitis,[3] lymph-node involvement by cryptococcus is not a common manifestation in AIDS patients as compared to other infections.[4]

A 17-year-old female presented with history of acute pain abdomen, anorexia, and weight loss for the past 5 months. The patient was being treated for tuberculosis since 3 months and was not responding to therapy. On physical examination, no lymph nodes were palpable. Ultrasonography of the abdomen was done, which showed enlarged mesenteric lymph nodes. Percutaneous ultra sono graphy (USG)-guided fine needle aspiration (FNA) of mesenteric lymph node was performed to rule out tuberculosis and lymphoma. Cultures and PCR for mycobacterium were requested. Cytological examination of FNA smears revealed abundant histiocytes, epithelioid granulomas, and multinucleated histiocytic giant cells in a necrotic background. Both histiocytes as well as giant cells revealed abundant intracytoplamic as well as extracellular small spores which were 2–15 μ in diameter, ovoid to spherical with a clear halo around them [Figure 1]. No abnormal lymphoid infiltrate was seen. Fungal stains with periodic acid-schiff (PAS) and diastase showed numerous fungal yeast forms, which were both intra and extracellular. These yeasts were variably sized and showed frequent, unequal sized narrow-based budding [Figure 2]. The capsule was positive for mucicarmine. Thus the morphology was consistent with the diagnosis of Cryptococcus neoformans. ZN stain for tubercle bacilli as well as culture and polymerase chain reaction (PCR) for mycobacterium were negative. Serological tests for HIV virus were positive. In this paper, the patient was admitted because of acute pain in abdomen, the rare presentation of mesenteric cryptococcosis. Therefore, a prompt diagnosis is mandatory in such situations for early initiation of treatment.

Figure 1

Abundant intracytoplamic as well as extracellular ovoid to spherical sporeswith a clear halo around them (Giemsa, ×100)

Figure 2

PAS stain revealing variably sized fungal yeasts with frequent, unequal sized narrow-based budding (PAS, ×100)

The laboratory diagnosis of cryptococcal infection includes the use of special stains, such as India ink, PAS-AB and mucicarmine stains, and serologic detection of cryptococcal antigen by latex agglutination and culture, which confirms the subtype of the organism. To this list, fine needle aspiration serology (FNAC) should be added as another investigative modality. An expeditious diagnosis is of utmost importance, since once cryptococcal infection disseminates, it becomes life threatening. Lymph-node FNAC is an ideal first-line diagnostic technique that can provide a definitive diagnosis considering the potential vast differential diagnosis in immunocompromised patients, resulting in prompt initiation of treatment.