Discussion:
PB-DLBCL is rare extranodal lymphoma which accounts for 2 percent of all
lymphomas in adult and the most common symptom is bone pain.
In this article, we report a 34-year-old man who presented progressive
hip pain and osteolytic bone lesions. He was later diagnosed with
primary diffuse large B-cell bone lymphoma ,previous studies had also
suggested that osteomyelitis unusually mimics PB-DLBCL (5-7)
Several rationales led us to believe that the previous workup session
was insufficient and another approach is needed to be taken, hence we
decided to perform an open biopsy, one of the main reasons to do so was
the fact that bone pain was progressive and unresponsive to the standard
antibiotic regimen.
On the other hand Radiologic changes, such as osteolytic lesions, were
progressive and despite regular treatment for osteomyelitis the lesions
progressed and contained sequestrum as the disease spread. this pattern
of progress was also observed between the two MRI scans that were taken
in the 6 months. These changes include an extraosseous extension of the
lesion that had led to asymmetric soft tissue swelling. These patterns
of change are usually seen with neoplastic lesions rather than
infectious ones.
In recent studies, it has been suggested that An ESR level of 60 mm/h is
an optimal cutoff level for suspected osteomyelitis. (74 % sensitive
and 56% specific), our patient had ESR levels below the threshold, thus
osteomyelitis seemed unlikely. (8)
Other reasons such as lack of predisposing factors for osteomyelitis
(i.e., Long term skin infections, Prosthetic joints, use of intravenous
drugs, etc.) and abrupt beginning of the symptoms made our case less
probable for osteomyelitis. Being safer and almost equally accurate it
has been suggested by the literature that core needle biopsy is a more
preferable method of obtaining bone tissue sample than open biopsy. it
is also both less invasive and cost-effective. (9)
unfortunately, though in our case core needle biopsy couldn’t help
provide an accurate diagnosis.
we have come to conclude that the first two biopsies were taken from the
rim of the lesion, thus making the sample redundant and inefficient. the
result was only suggestive for non-specific lymphocyte aggregation. In
such circumstances, open biopsy seems suitable for patients who are
highly suspicious of bone tumors and core needle biopsy is inconclusive
and non-diagnostic. (10)