A 67 year old woman with a 10 year history of rheumatoid arthritis (RA) treated with methotrexate and prednisone, presented with a 2 year history of worsening multiple cutaneous plaques of variable appearance. Two distinct skin lesions were biopsied to reveal a composite cutaneous lymphoma, possibly caused by long term methotrexate therapy. An [18F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) was performed to stage the malignancy, and was later repeated to evaluate response to chemotherapy, which guided subsequent management. We present the PET/CT imaging findings of this very rare iatrogenic (methotrexate induced) immunodeficiency-associated lymphoproliferative disorder.
Arthritis, Rheumatoid ; Composite Lymphoma ; Drug Therapy ; Electrons ; Female ; Humans ; Lymphoma ; Lymphoproliferative Disorders ; Methotrexate ; Positron-Emission Tomography and Computed Tomography ; Prednisone ; Skin

Follicular dendritic cell sarcoma (FDCS) is an extremely rare tumor with only 67 cases of head and neck FDCS reported in the literature. A 65-year-old female had a 6-cm follicular dendritic cell sarcoma resected from the left parotid gland with close margins. It recurred 1 year later as a 5-cm mass that was intensely [18F] fluoro-2-deoxy-D-glucose (18F-FDG) avid on positron emission tomography/computed tomography (PET/CT) and was re-excised. A follow-up PET/CT did not show any metastatic disease. The use of 18F-FDG PET/CT in the management of FDCS warrants further research. We present the 18F-FDG PET/CT imaging findings of this rare tumor.
Aged ; Dendritic Cell Sarcoma, Follicular ; Dendritic Cells, Follicular ; Electrons ; Female ; Fluorodeoxyglucose F18 ; Follow-Up Studies ; Head ; Humans ; Neck ; Parotid Gland ; Positron-Emission Tomography and Computed Tomography

Systemic lupus erythematosus (SLE) is associated with a variety of inflammatory processes that can affect the lymph nodes, brain, kidneys, and spleen. We present two patients with SLE in whom SLE-associated conditions complicated interpretation of ¹⁸F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) imaging of the lymph nodes and the spleen. The imaging findings mimicked lymphoma, but histopathological evaluation showed benign processes including reactive follicular hyperplasia in the lymph nodes, Kikuchi-Fujimoto disease in perisplenic lymph nodes, and inflammatory changes and lymphoid hyperplasia in the spleen.
Brain ; Electrons ; Histiocytic Necrotizing Lymphadenitis ; Humans ; Hyperplasia ; Inflammation ; Kidney ; Lupus Erythematosus, Systemic ; Lymph Nodes ; Lymphoma ; Positron-Emission Tomography and Computed Tomography ; Spleen

A 60 year old woman who presented with multiple small subcutaneous nodules in the upper back and arms, was referred for an [¹⁸F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) after histological evaluation revealed metastatic leiomyosarcoma of unknown origin. The PET/CT showed multiple ¹⁸F-FDG-avid subcutaneous nodules, bone lesions, as well as a large left renal mass, which was biopsied to confirm a primary renal leiomyosarcoma arising fromthe renal parenchyma.A post therapy PET/CT showed overall progression of disease. The use of 18F-FDG PET/CT in the staging and evaluation of response to therapy of a renal leiomyosarcoma has not been previously described in the literature.
Arm ; Electrons ; Female ; Fluorodeoxyglucose F18 ; Follow-Up Studies ; Humans ; Leiomyosarcoma ; Neoplasm Metastasis ; Positron-Emission Tomography and Computed Tomography

Systemic lupus erythematosus (SLE) is associated with a variety of inflammatory processes that can affect the lymph nodes, brain, kidneys, and spleen. We present two patients with SLE in whom SLE-associated conditions complicated interpretation of ¹⁸F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) imaging of the lymph nodes and the spleen. The imaging findings mimicked lymphoma, but histopathological evaluation showed benign processes including reactive follicular hyperplasia in the lymph nodes, Kikuchi-Fujimoto disease in perisplenic lymph nodes, and inflammatory changes and lymphoid hyperplasia in the spleen.

A 60 year old woman who presented with multiple small subcutaneous nodules in the upper back and arms, was referred for an [¹⁸F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) after histological evaluation revealed metastatic leiomyosarcoma of unknown origin. The PET/CT showed multiple ¹⁸F-FDG-avid subcutaneous nodules, bone lesions, as well as a large left renal mass, which was biopsied to confirm a primary renal leiomyosarcoma arising fromthe renal parenchyma.A post therapy PET/CT showed overall progression of disease. The use of 18F-FDG PET/CT in the staging and evaluation of response to therapy of a renal leiomyosarcoma has not been previously described in the literature.