惰性淋巴瘤大细胞转化的~(18)F-FDG PET/CT影像研究(附8例分析)

目的:探讨~(18)F-FDG PET/CT对惰性淋巴瘤大细胞转化的诊断价值.方法:回顾性分析8例惰性淋巴瘤转化前后~(18)F-FDG PET/CT影像,其中男性5例,女性3例,平均年龄53.5岁;8例转化前后均经病理及免疫组化染色证实.结果:8例惰性淋巴瘤最终均转化为弥漫大B细胞型淋巴瘤;其中6例由黏膜相关淋巴组织边缘区B细胞淋巴瘤(MALT)转化;1例由滤泡性淋巴瘤(FL)转化;1例由霍奇金结节性淋巴细胞为主性淋巴瘤(NLPHL)转化.转化前病灶~(18)F-FDG摄取呈轻度增高或无增高,平均SUV为2.2±1.0;转化后病灶~(18)F-FDG摄取明显增高,平均SUV为4.7±1.9;转化后病灶平均SUV明显高于转化前(P<0.01).结论:惰性淋巴瘤以小细胞为主,其增殖活性低,核分裂不明显,葡萄糖代谢水平较低,在PET/CT上病灶呈低摄取;转化成大细胞淋巴瘤增殖活性高,核分裂明显,葡萄糖代谢水平明显增高,提示~(18)F-FDG PET/CT随访可帮助判断惰性淋巴瘤发生大细胞转化.     

CT findings of lymphoma with peritoneal, omental and mesenteric involvement: peritoneal lymphomatosis

Purpose

We aimed to describe computed tomography (CT) findings in patients with peritoneal, omental and mesenteric lymphoma involvement.

Materials and methods

We searched our archive retrospectively to find out patients with peritoneal, omental and mesenteric lymphoma involvement. We found 16 patients with non-hodgkin lymphoma meeting these criteria. CT studies of these patients were reevaluated for the presence of peritoneal involvement, ascites, omental mass, organomegaly, retroperitoneal lymphadenopathy, bowel wall thickening and other associated findings.

Results

There were 14 males and 2 females with peritoneal and/or mesenteric and omental lymphoma involvement. Mean age was 39 (range 4-76). Subgroups of non-hodgkin lymphoma were diffuse large B-cell lymphoma (n = 11), small cell lymphocytic lymphoma (n = 2), small cleaved cell lymphoma (n = 1), T-cell lymphoma (n = 1) and Burkitt's lymphoma (n = 1). Peritoneal involvement was seen in 15 patients (93.8%) in the form of linear (n = 12) and nodular (n = 3) thickening. Ascites was seen in 12 (75%) patients. Omental and mesenteric masses were present in 10 (66.6%) and 10 (66.6%) patients, respectively. Bowel wall thickening, retroperitoneal lymphadenopathy and hepatosplenomegaly were also common and observed in 10, 10 and 11 patients, respectively. Solid organ involvement in the form of liver and splenic lesions was seen in 9 (56%) patients.

Conclusion

Peritoneal involvement can be seen in many subtypes of lymphoma and most frequently in diffuse large B-cell lymphoma. Peritoneal lymphomatosis can mimic peritoneal carcinomatosis and should be included in the differential diagnosis list in patients with ascites, hepatosplenic lesions and unidentified cause of peritoneal thickening on CT in a male patient.     

Utility of positron emission tomography/CT in the evaluation of small bowel pathology

We describe the management principles and different roles of positron emission tomography (PET)/CT in the evaluation of patients with small bowel tumours (adenocarcinoma, gastrointestinal stromal tumour, lymphoma, metastases) from initial staging, monitoring response to treatment, to detection of recurrent disease. We also discuss the various non-malignant aetiologies of small bowel fludeoxyglucose (FDG) PET uptake, and other pitfalls in FDG PET/CT interpretation. Awareness of the imaging appearances of small bowel tumours, patterns of disease spread and potential PET/CT interpretation pitfalls are of paramount importance to optimise diagnostic accuracy.     

18F-FDG uptake in diffuse peritoneal lymphomatosis

A 38-year-old man presented with declining appetite and progressive abdominal distention. Abdominal ultrasonography revealed omental and bowel wall thickening. Histopathologic examination showed a high-grade lymphoblastic Burkitt-like B-cell lymphoma. 18F fluorodeoxyglucose positron emission tomography/computed tomography images showed diffusely increased metabolic activity in the thickened omentum, intestines, mesentery, and peritoneum (omental caking). Diffuse peritoneal and omental seeding are well-known forms of dissemination of metastatic carcinoma. However, omental and peritoneal lymphomatosis are rare manifestations of high-grade lymphomas. This uncommon case demonstrates usefulness of F-18 fluorodeoxyglucose positron emission tomography/computed tomography in omental and peritoneal involvement in lymphoma.     

Primary peripheral T-cell lymphoma of the colon mimics inflammatory bowel disease: a potential pitfall with F-18 FDG PET/CT imaging

We present a case of a woman with ulcerative colitis who was referred for an F-18 FDG PET/CT after a suspicious colonoscopy and biopsy. PET/CT showed multiple elongated foci of intense FDG uptake in the colon, a pattern commonly reported with inflammatory bowel disease; however, the possibility of lymphoma was raised. Reevaluation of the biopsies with immunohistochemistry and molecular studies revealed a peripheral T-cell lymphoma and the patient was treated with a total colectomy. In this case, F-18 FDG PET/CT was very useful in determining the extent of the disease. This case also highlights a potential pitfall whereby the tubular and multifocal appearance of this lymphoma subtype can mimic the appearance of bowel involved by inflammatory bowel disease especially on novel techniques such as PET/CT enterography and PET/CT colonography.     

Intravascular large B-cell lymphoma with diffuse FDG uptake in the lung by 18FDG-PET/CT without chest CT findings

We report a rare case of intravascular large B-cell lymphoma (IVLBCL) with diffuse fluorodeoxyglucose (FDG) uptake in the lung by (18)FDG-positron emission tomography/computed tomography (PET/CT). CT showed nodular shadow, whereas diffuse FDG uptake in PET/CT suggested IVLBCL in the lung. A random skin biopsy provided histological evidence of IVLBCL. The patient responded well to combination chemotherapy. Only two cases of IVLBCL in which diffuse pulmonary FDG uptake was demonstrated have been reported previously. FDG-PET/CT plus random skin biopsy may be useful for the early diagnosis of IVLBCL with pulmonary involvement even without convincing radiological findings in the lung.     

肺内淋巴瘤的PET/CT影像表现分型

目的 总结恶性淋巴瘤(ML)肺侵犯的PET/CT影像学表现类型和特点,为正确诊断提供依据.方法 78例有肺侵犯的ML患者均经病理活组织检查证实,其中非霍奇金淋巴瘤(NHL)47例,霍奇金淋巴瘤(HL)10例,病理分型不明确的淋巴瘤21例.31例是因诊断不明确而;行PET/CT检查,发现并经病理检查确诊为ML,另47例已明确诊断者行PET/CT检查以了解肿瘤全身侵犯情况或有无复发、评价疗效.分析所有患者的PET/CT影像表现.结果 ML肺侵犯的影像表现形式各异,且同一病例可以同时出现不同的病变类型,大致可分为:(1)结节及肿块型(46例,含7例空洞型);(2)纤维索条及斑片型(29例);(3)胸膜心包侵犯型(23例);(4)双肺弥漫型(12例);(5)节段性或全肺不张型(9例);(6)环绕支气管肺门型(7例).除全身淋巴结组织和肺侵犯以外,还有其他部位的累及:骨皮质和骨髓内5例,胃3例,皮下软组织3例,乳腺1例,肾1例,肝1例,喉部1例.结论 PET/CT可以较准确地发现ML对肺的侵犯,显示病灶大小、形态和分布及肿瘤活性,为淋巴瘤的诊断和准确分期提供帮助.     

Clinical role of FDG PET/CT for methotrexate-related malignant lymphoma

Methotrexate-related malignant lymphoma (MTX-RML) is a type of therapy-related lymphoma, and it often occurs in patients with rheumatoid arthritis. The most distinctive characteristic of MTX-RML is a quick response to withdrawal of MTX. However, because there is a risk of recurrence without a distinctive indicator of disease, close follow-up is needed. We present F-18 2-fluoro-2-deoxyglucose (FDG) postitron emission tomography (PET) or computed tomography (CT) images of MTX-RML along with the characteristic clinical presentation of MTX-RML. FDG PET/CT has the advantage of being able to detect malignant lymphoma in patients who have undergone MTX treatment. After withdrawal of MTX, FDG uptake decreases along with a reduction in the volume of lesions. Although recurrent lesion develops independent to the initial FDG PET/CT findings, FDG PET/CT is useful for early detection of unexpected recurrent lesions. FDG PET/CT allows for the assessment of malignant lymphoma and recurrent lesions in patients who received MTX therapy, which is crucial for the management of MTX-RML.     

F-18 FDG PET/CT imaging of solitary genital tuberculosis mimicking recurrent lymphoma

A 65-year-old man who had multiple lymph nodes swelling was pathologically diagnosed with diffuse large B cell lymphoma. After initiation of induction chemotherapy, F-18 FDG PET/CT showed a significantly decreased extent of previous lymphomatous lesions except for 2 newly developed focal hypermetabolic lesions in the prostate and left epididymis. The specimens from the prostate and orchiectomy revealed tuberculosis lesions. After a 3-month antituberculosis regimen, there was definitively decreased glucose uptake in the prostate on F-18 FDG PET. F-18 FDG PET may be helpful for characterizing genitourinary tuberculosis and monitoring antituberculosis treatment.     

F-18 FDG PET/CT evaluation of radiotherapy response in rare case of mucosa-associated lymphoid tissue lymphoma

We experienced two cases of mucosa-associated lymphoid tissue (MALT) lymphoma arising at unusual locations and used F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to evaluate their response to radiation therapy (RT). A 62-year-old male with proven prostatic MALT lymphoma and a 43-year-old woman with proven duodenal MALT lymphoma had diffuse FDG uptake in the lesion. Both cases were treated with RT; following FDG, PET/CT showed decreased FDG uptake in each lesion. Neither patient had evidence of recurrence at more than 18 months after RT. FDG PET/CT is useful for indicating the treatment site in MALT lymphoma and in evaluation of therapeutic response following RT.     

F-18 FDG PET/CT findings of a case of sacral nerve root neurolymphomatosis that occurred during chemotherapy

Neurolymphomatosis (NL) is a rare, unique subtype of lymphomatous infiltration of peripheral nerves. Clinical/radiologic diagnosis of NL is challenging. We report F-18 FDG PET/CT findings of a case of breast diffuse large B-cell lymphoma, in which NL developed regardless of regression of systemic lesions during induction chemotherapy. FDG PET/CT showed characteristic findings of well-demarcated, linear abnormal FDG uptake along a sacral vertebral foramen, leading to diagnosis of NL, with the finding of thickened nerve roots on magnetic resonance imaging. Altered chemotherapeutic regimen resulted in disappearance of these abnormal FDG uptake, with recovery of neurologic symptoms. Peripheral nerve NL may occur during chemotherapy, and FDG PET/CT can be a useful imaging modality in diagnosis and monitoring of therapeutic response of this disease.     

Diagnosis of venous angiosarcoma by FDG PET/CT

A 56-year-old man with diffuse large cell lymphoma underwent posttherapy F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). A new focus of intense uptake was detected in contact with the left external iliac vein. This was biopsied and diagnosed as an angiosarcoma of the external iliac vein.     

Multimodality imaging of direct ureteric involvement in non-Hodgkin's lymphoma using PET/CT, CT urography and antegrade CT pyelography

Positron emission tomography/computed tomography (PET/CT), CT urography (CTU) and antegrade CT pyelography (ACTP) findings of ureteric involvement in non-Hodgkin's lymphoma (NHL) are presented. PET/CT performed for restaging in a patient with a 2-year history of Stage 4 NHL showed increased 2-[fluorine-18] fluoro-2-deoxy-D-glucose (FDG) activity in a distended ureteric segment. CTU and ACTP, performed to further evaluate PET/CT findings, demonstrated diffuse, irregular and concentric thickening of the affected ureteric walls, accompanied by severe irregular narrowing of affected ureteric lumen. Tissue sampling using percutaneous CT-guided biopsy revealed NHL involvement of the ureter. To the best of our knowledge, this is the first report of PET/CT, CTU and ACTP findings of ureteric NHL.     

Fat necrosis mimicking B-cell lymphoma: a PET/CT and FDG study

F-18 fluoro-2-deoxyglucose positron emission tomography combined with computed tomography (FDG and PET/CT) is increasingly becoming the standard in staging and restaging patients with a range of malignancies including B-cell lymphoma. However, there are well-known pitfalls in PET/CT with FDG imaging, which comprise infection, inflammation, physiological variants, and benign pathologic conditions. Fat necrosis is the result of death of adipose tissue from disease, injury, or pathologic conditions. We describe a case of false positive PET/CT and FDG scan in a patient with fat necrosis mimicking B-cell lymphoma after 6 cycles of rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) treatment. In interpreting PET/CT and FDG images with inconsistency in lesion response, fat necrosis should be considered in the differential diagnosis.     

F-18 FDG positron emission tomography in non-Hodgkin lymphoma of the breast

The breast is an uncommon site of development of extranodal non-Hodgkin lymphoma (NHL). Both primary and secondary involvement of the breast have been reported. A 36-year-old woman diagnosed with NHL underwent multimodality imaging for staging of the disease. CT of the chest revealed no significant abnormalities. Whole-body FDG PET imaging showed intense FDG uptake in the left breast. Cytologic examination confirmed breast involvement by diffuse large B-cell NHL. Although rare, breast involvement characterized by increased FDG uptake can occur in patients with lymphoma. This case highlights the role of FDG PET in patients with suspected lymphoma in dense breasts that can be missed by CT scan and mammogram.     

PET/CT and renal pathology: a blind spot for radiologists? Part 2--lymphoma, leukemia, and metastatic disease

OBJECTIVE: PET/CT with (18)F-FDG is a powerful tool to evaluate patients with hematologic malignancy or to assess the burden of metastatic disease from solid tumors. Metabolically active renal pathology associated with lymphoma, leukemia, or metastatic disease can be missed without close attention to both the PET and CT portions of the study because of physiologic FDG excretion in the kidneys. This article illustrates the appearance of tracer uptake and the key anatomic features of lymphoma, leukemia, and metastatic disease involving the kidney on FDG PET/CT. CONCLUSION: Close attention to both the FDG PET and CT portions of an FDG PET/CT study is essential to evaluate the kidneys in oncology patients.     

Detection of small bowel involvement by mantle cell lymphoma on F-18 FDG positron emission tomography

F-18 fluorodeoxyglucose positron emission tomography (FDG PET) is highly sensitive and specific for the detection of nodal and extranodal disease in patients with malignant lymphoma. However, no previous reports have shown lymphomatous involvement of the small bowel that was recognized on the basis of FDG-PET imaging findings. The authors present two cases of clinically unsuspected small bowel involvement by mantle cell lymphoma that were initially detected on FDG PET.     

Findings of fluorine-18-FDG PET in extranodal origin lymphoma —In three cases of diffuse large B cell type lymphoma—

F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is an excellent modality for non-invasive functional imaging of malignant lymphoma and is highly sensitive and specific for the detection of lymphoma lesions. Here, we report the findings of FDG-PET for three cases of diffuse large B cell type lymphoma (DLBCL) with extranodal tumors in the breast, stomach, and liver plus spleen, respectively. The whole body FDG-PET findings showed no evidence of lymph node (LN) involvement or distant metastasis. Strong FDG accumulations were observed in the only extranodal sites by whole body FDG-PET. Therefore, we could confirm that these cases were extranodal primary origins. Whole body PET is useful to determine the primary sites, that is, extranodal origin DLBCL with its clear images.     

PET and PET–CT imaging findings of peritoneal and omental involvement in patients with lymphoma

A retrospective institutional-review-board-approved study was performed evaluating positron emission tomography (PET)–computed tomography (CT) imaging findings of peritoneal and omental involvement of lymphoma. Twelve patients were identified with a wide spectrum of imaging findings on PET–CT including but not limited to peritoneal thickening, ascites, and serosal involvement. Lymphoma is among the rare causes of malignant peritoneal or omental involvement. The most common manifestations of peritoneal lymphomatosis are peritoneal 2-[fluorine 18] fluoro-2-deoxy-d-glucose uptake with corresponding peritoneal thickening and nonobstructive serosal masses on CT.     

Multiple intraabdominal purulent collections demonstrated on FDG PET/CT in staging of non-Hodgkin lymphoma

A 56-year-old man, recently diagnosed with non-Hodgkin lymphoma, was referred for a FDG PET/CT scan to stage disease. Unexpected large fluid collections with FDG-avid peripheries and central photopenia were demonstrated in the abdomen and pelvis on the FDG PET/CT study. The collections were urgently drained with subsequent resolution. After antibiotic treatment, repeat FDG PET/CT study confirmed rapidly progressive lymphoma necessitating urgent chemotherapy.