Speckled-egg staining appearance of cryptococcal osteomyelitis in an immunocompetent patient

Cryptococcal infections are typically thought of as occurring in immunocompromised patients, such as patients with HIV/AIDS, solid organ transplant recipients, or patients with rheumatologic diseases that require immunomodulatory therapy. Moreover, Cryptococcus spp. classically appear as variably-sized yeasts with narrow-based budding surrounded by a thick polysaccharide capsule. However, cryptococcal infections are being increasingly reported in atypical hosts, at times with non-characteristic histochemical staining appearances. Herein, we report a case of cryptococcal osteomyelitis in an otherwise immunocompetent individual that had a "speckled-egg" staining appearance on direct-smear Gram stain.

The patient is an otherwise healthy 89-year-old male with a past medical history notable only for hypertension who presented with progressive left-sided neck pain that became worse despite lidocaine trigger point injections; imaging was obtained and revealed a C1-C2 prevertebral abscess, C2-C4 osteomyelitis, and a small C2-C4 abscess. An aspiration biopsy from one of the cervical abscesses grew Cryptococcus neoformans. Despite prompt initiation of liposomal amphotericin B as soon as the organism was suspected, the patient's mentation declined with associated progression of weakness in his upper and lower extremities. The patient was ultimately transitioned to comfort care.

Unconventional presentations of cryptococcal disease are becoming increasingly recognized in seemingly immunocompetent patients. Our case was unique given that it occurred in a patient who appeared to be immunocompetent and the Gram stain showed a speckled-egg staining pattern that alone was not distinctive for cryptococcal yeasts. Despite the patient's lack of any classic comorbidities associated with invasive cryptococcal disease, his advanced age was likely a risk factor.