Cancer Res Treat.  2009 Sep;41(3):171-174.

F-18 FDG PET-positive Fibrous Dysplasia in a Patient with Intestinal Non-Hodgkin's Lymphoma

• Kim M
• Kim HS
• Kim JH
• Jang JH
• Chung KJ
• Shin MK
• Hwang HS
• Kim BC
• Jung SY

Abstract

Fibrous dysplasia (FD) is a common benign bone disorder of an unclear etiology. It is known that FD can appear without an increased FDG uptake on F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT). However, there are also several reports that FD showed increased FDG uptake and this mimicked malignant bone involvement on FDG-PET. Herein we describe a case of biopsy-proven FDG-PET positive FD in a patient with intestinal non-Hodgkin's lymphoma (NHL). A 45-year-old woman was diagnosed with intestinal NHL, which was removed by right hemicolectomy. After the operation, the FDG-PET/CT scan showed hypermetabolic activity in the right transverse process of the T10 vertebra. The patient then received a total of 6 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) chemotherapy every 3 weeks. After completion of the planned chemotherapy, the 2nd FDG-PET/CT showed increased FDG uptake (SUVmax=6.0 g/mL) of the previous bone lesion. The MR images revealed a T1-hypointense lesion with sharp borders in the same region, and this showed homogenous contrast enhancement on the fat-suppressed T1-weighted images. After the radiologic studies were carefully reviewed, the bone lesion was assumed to be benign such as FD. We performed bone biopsy and the histological examination confirmed the diagnosis of FD. In conclusion, bone lesions with FDG uptake need to be carefully interpreted when evaluating patients with known malignancy.

Keyword

Fibrous dysplasia; Non-Hodgkin lymphoma; FDG-PET

MeSH Terms

Biopsy
Cyclophosphamide
Doxorubicin
Electrons
Female
Humans
Lymphoma, Non-Hodgkin
Middle Aged
Spine
Vincristine
Cyclophosphamide
Doxorubicin
Vincristine

Figure

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  Fig. 1 (A) The initial FDG-PET/CT examination at the time of diagnosis of the diffuse large B-cell lymphoma demonstrates moderate FDG hypermetabolism (SUVmax=3.1 g/mL) in a right transverse process of the T10 vertebra (arrow). (B) Six months later after completion of the planned systemic chemotherapy, the follow-up PET/CT scan demonstrates further increased FDG hypermetabolic activity (SUVmax=6.0 g/mL) (arrow).

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  Fig. 2 The axial T1 weighted MR image shows a hypo-intense lesion (A, arrow) and the axial contrast-enhanced, fat-suppressed MR image shows homogeneous contrast enhancement of the well-defined lesion (B, arrow).

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  Fig. 3 Hematoxyline and eosin staining of the surgical biopsy specimen of the right transverse process of the T10 vertebra demonstrates bone trabeculae without osteoblastic rimming and there is bland spindle-cell proliferation. The bone trabeculae are composed of immature and disorganized osteoid (H & E, ×40).

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