Prepared by
Timothy C. Sloan, DVM, MD
, a Radiologist at Coastal Radiology, New Bern, SC and
Jason Hosey, MD,
a Resident of Diagnostic Radiology at The Medical University of
South Carolina, Charleston, SC.
CASE SUMMARY
A 51-year-old man presented to the emergency department with
chest pain radiating to the right shoulder. The pain had been
present for several months but had become refractory to analgesics.
Past medical history was remarkable for recently diagnosed diabetes
mellitus with negative cardiac and gastrointestinal workups.
Physical examination revealed the patient had a low-grade fever and
pain localized over the midthoracic spine. A radiograph of the
thoracic spine (Figure 1) prompted subsequent computed tomography
(CT; Figure 2) and magnetic resonance (MR; Figure 3)
examinations.
DIAGNOSIS
Cryptococcal osteomyelitis
IMAGING FINDINGS
Radiography of the thoracic spine demonstrated compression
fracture of T6 (Figure 1). CT demonstrated a paravertebral
soft-tissue mass with destruction of T6 vertebral bodies, posterior
elements, and posterior left rib (Figure 2). MR imaging revealed
abnormal enhancement within the T6 vertebral body with sparing of
the adjacent intervertebral discs (Figure 3).
DISCUSSION
Cryptococcus neoformans
is a ubiquitous yeast (Figure 4) that grows abundantly in soil
containing bird (especially pigeon) droppings. Disseminated
infection of man and animals occurs mainly in the
immunocompromised, with the lungs and central nervous system most
commonly affected. Approximately 50% of patients with cryptococcal
meningitis, however, show no evidence of immunosuppression.
Osteomyelitis occurs in 5% to 10% of disseminated cases, but
isolated bone involvement is rare. Crypto-coccal meningitis is
common in HIV-infected patients; however, no case of cryptococcal
osteomyelitis has been reported in this population.
A recent review of 40 reported cases found most cases involved
one site. The most common site was the spine, followed by the
femur, tibia, humerus, and ribs. The most common comorbidity was
sarcoidosis, followed by tuberculosis, steroid therapy, and, as in
this case, diabetes mellitus.
Differential diagnostic considerations include tuberculosis,
plasmacytoma, metastatic disease, and lymphoma.