2. First case
The first case was a 59-year-old woman in 2012 with no past history, who
presented with a painful right frontal tumefaction above the eyebrow. No
growth bone or other abnormality was observed at the radiography. The
scan showed a frontal anterior right tissue process up to the external
part of the right frontal sinus and a lytic bone lesion beginning at the
right orbit roof. The biopsy of the frontal lesion was inconclusive and
suggested only a chronic lymphoproliferative disorder (CLPD) without
further clarification. Proofreading of the frontal bone biopsy confirmed
a bone localization of HCL with a BRAFV600E mutation
positive (mutation identified in 70-100% of typical HCL cases) (2). The
bone marrow biopsy revealed moderate infiltration by hairy cells
expressing DBA44, cycline D1 and CD20 as well. The markers of
T-lymphoproliferation disorders and extramedullary plasmocytoma were
negative. The bone marrow aspirate showed a smear of medium richness on
which the different myeloid cell lines were correctly represented
without morphological abnormalities. No excess of blasts was observed,
despite the presence of medium-sized lymphoid cells with basophil
cytoplasm, and often with “shredded” appearance and circular and
reniform nucleus with the chromatin unpacked. This confirmed the
presence of around 6% of lymphoid cells whose cytological appearance
suggested hairy cells. The phenotype was compatible to hairy cells CD19+
monotypic kappa of moderate intensity CD5- CD10- CD20+ high CD22+ high
CD79b+ CD23- FMC7- CD38+ CD43- CD44+ IgG- IgM+ IgD- CD11c+ CD25+ CD103+
CD123+. The immunological score of HCL was 4/4, excluding a variant
presentation. In order to assess the extension consecutive to the
histology of the frontal bone lesion, 18F-FDG PET/CT
was carried out. Three bone hypermetabolisms were reported: the known
frontal bone lesion, one on the right semi-sacrum and the third on the
hipbone, near the sacroiliac joint. The body scan did not identify focal
lesion or lytic bone lesion at the hipbone but rather a bone
densification, and no tumor syndrome was described. The patient was
symptomatic only on the frontal lesion. The complete blood count was
normal except for minimal thrombocytopenia: white blood cells at
4.8x109/L composed of 3.07x109neutrophils/L, 1.58x109 lymphocytes/L and
0.1x109 monocytes/L, hemoglobin was 14,2g/dL and
platelets were at 148x109/L (lower limit at
150x109/L).
Because of long initial diagnostic wandering and the emergency of a
treatment required in fear of a rapid progression of the orbit roof
osteolytic lesion in case of diffuse large cell lymphoma, two cycles of
CEP (cyclophosphamide, etoposide, prednisolone) were administered with
no clinical benefit observed. As soon as the final histology of the bone
marrow biopsy was received, the standard first-line treatment by purine
analog, cladribine (CDA), was initiated.
Two months after the treatment, neither symptom nor pain, was reported
by the patient. A complete response (CR) was obtained on both medical
examination, blood count and scan. Six months after the treatment, the18F-FDG PET/CT done described a disappearance of
hypermetabolisms on the right frontal bone, and of the sacrum and right
hip bone at pelvic girdle. However, the bone marrow aspirate evaluation
done at the 6-month treatment evaluation showed normal bone marrow
cytology without lymphoid cells but also minimal residual disease of
hairy cells of 0.3% of bone marrow cells. A total of four weekly
rituximab was subsequently administered. With a follow-up of eight years
after the treatment, no objective relapse had occurred.