Imaging of musculoskeletal lymphoma

Diagnostic challenge: Combination of magnetic resonance imaging and serum soluble Interleukin-2 receptor in soft tissue non-hodgkin lymphoma

Purpose

Non-Hodgkin lymphoma (NHL) sometimes occurs in soft tissue (referred to as soft tissue lymphoma or soft tissue NHL), often mimicking soft tissue tumors. Despite some clinical indicators, accurate diagnosis of soft tissue NHL before biopsy remains challenging. We investigated the diagnostic value of serum soluble interleukin-2 receptor (sIL-2R) levels and magnetic resonance imaging (MRI) as an initial tool to assess the likelihood of soft tissue NHL.

Methods

We analyzed 36 cases of pathologically proven soft tissue NHL initially suspected as soft tissue tumors alongside 48 control cases of soft tissue sarcoma or carcinoma. Patient medical charts and MRI scans were retrospectively reviewed and statistically analyzed, focusing on assessing the diagnostic efficacy of soft tissue NHL.

Results

The diagnostic accuracy of soft tissue NHL combining the appearance of homogeneity on MRI (T2-weighted and/or short-time inversion recovery [STIR] images) and sIL-2R value (≧ 904 U/mL) yielded a sensitivity of 78 % and 86 %, and specificity of 83 % and 88 %, respectively. Meeting one or both criteria increased the sensitivity to a maximum of 92 %, albeit with a specificity of 71 %. When both criteria were met, sensitivity and specificity were 72 % and 100 %, respectively.

Conclusion

The integrated approach of combining MRI and sIL-2R demonstrated excellent efficacy in predicting the diagnosis of soft tissue NHL, which was initially referred to as soft tissue tumor.

Primary extranodal diffuse large b-cell lymphoma of the calf muscle mimicking a carcinoma: A rare case report

INTRODUCTION AND IMPORTANCE

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma (NHL), known for its aggressive nature and tendency for extranodal extension. Extranodal involvement occurs in up to 40 % of cases, with primary lymphoma in soft tissue, particularly skeletal muscle, being exceedingly rare. This report presents a rare case of primary extranodal DLBCL in the calf muscle.

CASE PRESENTATION

A 35-year-old man presented with an ulceroproliferative growth in left calf muscle, initially diagnosed as squamous cell carcinoma (SCC). Imaging studies, including CECT and MRI, were inconclusive, prompting a histological examination. Biopsy revealed large malignant cells with high mitotic activity, positive for LCA, CD20, BCL-2, MUM1, and CD10, confirming a diagnosis of primary extranodal DLBCL. The patient underwent resection followed by six cycles of chemotherapy (R-CHOP) and field radiation therapy. A follow-up PET showed significant improvement, with no evidence of disease recurrence.

CLINICAL DISCUSSION

DLBCL often presents with rapidly growing tumors in lymph nodes or extranodal sites. Primary skeletal muscle lymphoma, particularly of the DLBCL subtype, is extremely rare, constituting about 0.5 % of extranodal lymphomas. Diagnosis typically involves imaging and biopsy, with immunohistochemistry (IHC) being crucial for accurate classification and treatment planning.

CONCLUSION

DLBCL, while common among NHLs, rarely presents as primary extranodal lymphoma in skeletal muscle. The presented case underscores the importance of considering DLBCL in differential diagnoses for atypical soft tissue masses and the effectiveness of R-CHOP chemotherapy in managing this rare presentation. Prompt and appropriate treatment, such as R-CHOP chemotherapy, is essential for favorable outcomes.

Typical and Atypical Imaging Features of Malignant Lymphoma in the Abdomen and Mimicking Diseases

Malignant lymphoma typically presents with homogeneous enhancement of enlarged lymph nodes without internal necrotic or cystic changes on multiphasic CT, which can be suspected without invasive diagnostic methods. However, some subtypes of malignant lymphoma show atypical imaging features, which makes diagnosis challenging for radiologists. Moreover, there are several lymphoma-mimicking diseases in current clinical practice, including leukemia, viral infections in immunocompromised patients, and primary or metastatic cancer. The ability of diagnostic processes to distinguish malignant lymphoma from mimicking diseases is necessary to establish effective management strategies for initial radiological examinations. Therefore, this study aimed to discuss the typical and atypical imaging features of malignant lymphoma as well as mimicking diseases and discuss important diagnostic clues that can help narrow down the differential diagnosis.

From open wound treatment to primary soft-tissue non-Hodgkin lymphoma diagnosis; a challenging case report

Primary soft-tissue extranodal lymphomas are rare clinical entities. By their natures, they can cause significant swelling around the affected extremities, and they can be easily misdiagnosed with other conditions like sarcomas. We share an unfortunate experience of a young male patient who was admitted to another clinic with complaints of a large mass in his right thigh, the patient has been diagnosed with anaplastic pleomorphic sarcoma, and he was scheduled for surgery. The patient refused the operation and was admitted to our emergency clinic with an open wound on his right thigh. Successful open wound management was achieved with antibiotic therapy, tissue debridement, larvae therapy, and Vacuum-assisted closure. Meanwhile, the pathologic re-examination revealed diffuse large B-cell lymphoma. After an uneventful follow-up, the patient was referred to the hematology clinic. This case highlights the importance of considering alternative diagnoses before making surgical intervention decisions that may result in unpleasing consequences.

Diagnostic value of FDG-PET/CT in fever of unknown origin

Background

Fever of unknown origin (FUO) is a challenging clinical problem in medicine that needs collaboration of various diagnostic techniques to establish the accurate diagnosis. We evaluated the diagnostic performance of 18F-FDG PET/CT in patients who presented themselves with FUO. Our study included 40 patients with FUO who underwent PET/CT examination and their results were compared to the results of laboratory, histopathological, microbiological investigations and/or response to therapy.

Results

The final diagnosis included malignancy in 20 patients (50%), infectious causes in 7 patients (17.5%) and non-infectious inflammatory causes in 6 patients (15%). Fever resolved without diagnosis in 4 patients (10%), while no definite diagnosis was reached in 3 patients (7%). PET/CT successfully contributed to diagnosis of 35 out of 40 patients with diagnostic accuracy of 87.5%. The sensitivity, specificity, positive predictive value and negative predictive value of PET/CT in our study were 93.5%, 66.7%, 90.6% and 75%, respectively.

Conclusion

PET/CT is a useful tool to investigate and diagnose the cause of FUO. It provides information that can guide the treatment strategy of the patients.

Musculoskeletal manifestations of lymphoma: a case series

Lymphomas are a heterogenous group of cancers of the lymphatic system in which disease primarily arises in lymph nodes. Extranodal disease is common; however, musculoskeletal involvement is rare. Imaging plays an important role in the diagnosis and staging of all lymphomas. In this case series, we present examples of musculoskeletal involvement of lymphoma encountered at our institution. We outline the clinical presentation and imaging findings of each and use these cases to review the features that can help to differentiate lymphoma from other musculoskeletal lesions.

Clinical Presentation and MRI Characteristics of Appendicular Soft Tissue Lymphoma: A Systematic Review

Appendicular soft tissue lymphoma (ASTL) is rare and is frequently misinterpreted as soft tissue sarcoma (STS). Studies investigating magnet resonance imaging (MRI) characteristics of ASTL are scarce and showed heterogenous investigation criteria and results. The purpose of this study was to systematically review clinical presentations and MRI characteristics of ASTL as described in the current literature. For that purpose, we performed a systematic literature review in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Patient demographics, clinical presentation and MRI imaging characteristics of ASTL were investigated, resulting in a total of nine included studies reporting a total of 77 patients. Signal intensity of lymphoma compared to muscle tissue was mostly described as isointense (53%) or slightly hyperintense (39%) in T1-weighted images and always as hyperintense in proton-and T2-weighted images. Multicompartmental involvement was reported in 59% of cases and subcutaneous stranding in 74%. Long segmental involvement was present in 80% of investigated cases. Involvement of neurovascular structures was reported in 41% of cases and the presence of traversing vessels in 83% of patients. The presence of these findings should lead to the inclusion of ASTL in the differential diagnosis of soft tissue masses.

Non-Hodgkin Lymphoma Imaging Spectrum in Children, Adolescents, and Young Adults

In children, adolescents, and young adults (CAYA), non-Hodgkin lymphoma (NHL) is characterized by various age-related dissimilarities in tumor aggressiveness, prevailing pathologic subtypes, and imaging features, as well as potentially different treatment outcomes. Understanding the imaging spectrum of NHL in CAYA with particular attention to children and adolescents is critical for radiologists to support the clinical decision making by the treating physicians and other health care practitioners. The authors discuss the currently performed imaging modalities including radiography, US, CT, MRI, and PET in the diagnosis, staging, and assessment of the treatment response. Familiarity with diagnostic imaging challenges during image acquisition, processing, and interpretation is required when managing patients with NHL. The authors describe potentially problematic and life-threatening scenarios that require prompt management. Moreover, the authors address the unprecedented urge to understand the imaging patterns of possible treatment-related complications of the therapeutic agents used in NHL clinical trials and in practice. Online supplemental material is available for this article. ^©RSNA, 2022.

Chronic Heel Pain Found to Be Diffuse Large B-cell Lymphoma of the Calcaneus

Primary non-Hodgkin lymphoma of the bone is quite rare, accounting for less than 2% of all lymphomas in adults. We present a unique case of chronic left heel pain in a 34-year-old pregnant woman with a remote history of lower extremity trauma. Unresponsive to conservative treatment, advanced imaging showed an infiltrative soft tissue mass involving the calcaneus and surrounding soft tissues. Biopsy of the area confirmed the diagnosis of Stage I-AE diffuse large B-cell lymphoma. The patient underwent 20 localized radiation treatments to the left heel. Nine years after the diagnosis, the patient remains in remission without signs of disease recurrence. This case report demonstrates that atypical and less common causes of chronic heel pain should be considered in certain clinical scenarios, especially in those unresponsive to conservative treatment.

Isolated pathologies of Tensor Fasciae Latae: Retrospective cohort analysis from a tertiary referral centre

INTRODUCTION

Tensor Fasciae Latae (TFL) and the iliotibial band (ITB) act as a single functional unit in maintaining pelvic stability whilst standing, walking, or running in human beings. The Tensor Fasciae Latae (TFL) muscle acts across the hip and the knee joint. Consequently, though its pathologies traditionally present with lateral hip pain, identifying the precise clinical diagnosis can be a challenge.

PATIENTS AND METHODS

A retrospective search for the keyword 'Tensor Fasciae Latae'/iliotibial band (ITB) was performed of our Radiology Information System (RIS) and Picture Archiving and Communication System (PACS), Computerised Radiology Information System (CRIS) at our tertiary orthopaedic referral centre of a for orthopaedic oncology over a period of 13 years (2007-2020). Data was collected from RIS, oncology database and local histopathology laboratory records. Patient demographics, clinical characteristics, complementary imaging and clinical management outcome were documented.

RESULTS

We identified 35 patients with a mean age of 66 years (range 19-94 years). There were 18 female and 17 male patients. Lateral hip lump and pain were the most frequent clinical finding/presentation features. A variety of pathologies such as benign and malignant tumours, including vascular and tumour mimic lesions involving the TFL muscle were identified. Atrophy and pseudohypertrophy of TFL was the commonest pathology found; accounting for two thirds of the cases.

CONCLUSION

Tensor Fasciae Latae (TFL) can be afflicted with a broad spectrum of pathologies. Radiological imaging especially cross-sectional imaging modality is crucial in guiding appropriate patient management of TFL conditions. Our analysis suggests isolated TFL lesion are more likely to be benign conditions, presenting commonly as hip pain and swelling.

Imaging findings of malignant skin tumors: radiological-pathological correlation

Sometimes, radiologists encounter malignant skin tumors (MSTs) during image interpretation. As MSTs require different clinical management modalities for each histological subtype, accurate preoperative diagnosis is essential. The histological subtypes of MST can be easily assessed by visual inspection or biopsy. Therefore, the significant role of radiological imaging in MSTs is to evaluate the extent of local invasion, nodal involvement, and distant metastasis, and the histological estimation of MSTs by radiological imaging has not been reported until a few years ago. However, recent studies have revealed characteristic radiological features for differential diagnosis of MSTs, such as configuration, intratumoral homogeneity, signal intensity, cyst formation, and hemorrhage. Other important clinical data for determining the histological subtype of MST include age, gender, and site of occurrence. MSTs can be categorized as epidermal, melanocytic, adnexal, and mesenchymal tumors based on the origin and have distinctive characteristics. Hence, this review article was designed to describe the clinical and radiological features of MSTs.

Common Skeletal Neoplasms and Nonneoplastic Lesions at 18F-FDG PET/CT

Numerous primary and metastatic osseous lesions and incidental osseous findings are encountered at fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT. These lesions show varying degrees of FDG uptake. Malignancies are generally more FDG avid than are benign lesions, but many exceptions exist. Although aggressive lesions tend to be more FDG avid than nonaggressive lesions, this concept holds true particularly for lesions of the same histologic subtype. In addition, some benign osseous processes such as Paget disease have variable degrees of FDG avidity on the basis of disease metabolic activity. This creates a diagnostic dilemma for radiologists and clinicians, especially in patients with known malignancies, and can result in unnecessary diagnostic imaging or interventions for incidental osseous lesions. Evaluation of morphologic CT characteristics of osseous lesions at FDG PET/CT can be a valuable adjunct to metabolic analysis to further characterize lesions, enhance diagnostic and staging accuracy, and avoid unnecessary invasive biopsy procedures. The authors review the common primary and metastatic bone lesions at FDG PET/CT, with an emphasis on morphologic CT assessment of lesions to help narrow the differential diagnosis. Imaging manifestations of common incidental nonneoplastic bone lesions at FDG PET/CT are discussed to provide information on differentiation of these lesions from osseous neoplasms. The guidelines of the National Comprehensive Cancer Network (NCCN) for common primary osseous malignancies are also summarized. Online supplemental material is available for this article. ^©RSNA, 2021.

Disseminated soft tissue diffuse large B-cell lymphoma involving multiple abdominal wall muscles: A case report

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma, and patients with DLBCL typically present rapidly growing masses. Lymphoma involving muscle is rare and accounts for only 5%; furthermore, multiple muscles and soft tissue involvement of DLBCL is unusual. Due to unusual clinical manifestation, accurate diagnosis could be delayed.

CASE SUMMARY

A 61-year-old man complained of swelling, pain and erythematous changes in the lower abdomen. Initially, soft tissue infection was suspected, however, skin lesion did not respond to antibiotics. ¹⁸Fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography-computed tomography demonstrated FDG uptake not only in the skin and subcutaneous tissue of the abdomen but also in the abdominal wall muscles, peritoneum, perineum, penis and testis. DLBCL was confirmed by biopsy of the abdominal wall muscle and subcutaneous tissue. After intensive treatment including chemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone, central nervous system prophylaxis (intrathecal injection of methotrexate, cytarabine and hydrocortisone) and orchiectomy, he underwent peripheral blood stem cell mobilization for an autologous hematopoietic stem cell transplantation. Despite intensive treatment, the disease progressed rapidly and the patient showed poor outcome (overall survival, 9 mo; disease free survival, 3 mo).

CONCLUSION

The first clinical manifestation of soft tissue DLBCL involving multiple muscles was similar to the infection of the soft tissue.

Imaging features of skeletal muscle lymphoma: a case report and literature review

BACKGROUND

Diffuse large B cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL), occurring predominantly in older people. Skeletal muscle lymphoma is a rare form of DLBCL, most frequently affecting the thigh, upper extremities, calf, and pelvis.

CASE PRESENTATION

We report a case of skeletal muscle DLBCL that was diagnosed using ultrasound (US)-guided biopsy. A 70-year-old man presented with progressive swelling and pain in the left lower extremity and an elevated erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP), ferritin, and CA125 levels. US, magnetic resonance imaging (MRI), and computed tomography (CT) showed diffuse lesions in several muscles of the left lower extremity. Positron emission tomography/CT (PET/CT) showed FDG-uptake in the affected muscles. The patient was treated with chemotherapy and achieved a good response. A systematic review of the literature published between 1992 and 2019 was conducted to investigate the role of imaging, including imaging-guided biopsy, in the diagnosis of skeletal muscle lymphoma.

CONCLUSIONS

Skeletal muscle lymphoma is rare. US and MRI features include enlargement of muscular structures, with preservation of the architecture of the tissue and surrounding anatomical structures. Definitive diagnosis relies on histological and immunohistological analysis of a sample obtained through imaging-guided biopsy.

Imaging Spectrum of Calvarial Abnormalities

Calvarial abnormalities are usually discovered incidentally on radiologic studies or less commonly manifest with symptoms. This narrative review describes the imaging spectrum of the abnormal calvaria. The extent, multiplicity, and other imaging features of calvarial abnormalities can be combined with the clinical information to establish a final diagnosis or at least narrow the differential considerations. Prior trauma (congenital depression, leptomeningeal cysts, posttraumatic osteolysis), surgical intervention (flap osteonecrosis and burr holes), infection, and inflammatory processes (sarcoidosis) can result in focal bone loss, which may also be seen with idiopathic disorders without (bilateral parietal thinning and Gorham disease) or with (Parry-Romberg syndrome) atrophy of the overlying soft tissues. Anatomic variants (arachnoid granulations, venous lakes, parietal foramina) and certain congenital lesions (epidermoid and dermoid cysts, atretic encephalocele, sinus pericranii, and aplasia cutis congenita) manifest as solitary lytic lesions. Other congenital entities (lacunar skull and dysplasia) display a diffuse pattern of skull involvement. Several benign and malignant primary bone tumors involve the calvaria and manifest as lytic, sclerotic, mixed lytic and sclerotic, or thinning lesions, whereas multifocal disease is mainly due to hematologic or secondary malignancies. Metabolic disorders such as rickets, hyperparathyroidism, renal osteodystrophy, acromegaly, and Paget disease involve the calvaria in a more diffuse pattern. Online supplemental material is available for this article. ^©RSNA, 2021.

Transarticular epithelioid hemangioma of the ankle-a case of a rare vascular neoplasm

Epithelioid hemangioma of the bone is a rare kind of vascular neoplasm posing a diagnostic challenge because of its ability to mimic malignant tumors. We report a case of a fast-growing, talofibular joint-involving epithelioid hemangioma, which was suspectedly initiated by vascular damage due to trauma and arthroscopy. The ankle mass appeared as a lytic lesion on the CT images and as a T1 hypo-, T2 mildly hyperintense, lobulated structure on the MRI scans. The contrast enhancement pattern was typical to vascular neoplasms. Histologically the lesion consisted of well-formed vessels lined with epithelioid cells with a slightly atypical nuclear morphology, inflammation with a significant number of eosinophils, and low mitotic rate. Immunohistochemistry analysis showed the presence of vascular markers but no rearrangements characteristic of soft tissue sarcomas were registered by the next-generation sequencing. The surgical treatment was curative. The report presents current imaging methods and summarizes the imaging findings of transarticular spreading tumors. The paper also highlights that for the differential diagnosis of vascular tumors showing signs of aggressivity, the pathological analysis is inevitable. Correct diagnosis of the epithelioid hemangioma is essential, as the treatment of more malignant entities is substantially different. An added value of the report is that to the best of our knowledge, a transarticular spreading epithelioid hemangioma of the ankle has never been described before.

Radiogenomics and Its Role in Lymphoma

PURPOSE OF REVIEW

Imaging features of lymphoma vary regionally. Awareness of site-specific key imaging characteristics of lymphoma can aid in rapid staging and assist in prompt treatment. FDG PET/CT and conventional MRI are readily available diagnostic modalities with excellent sensitivity and good specificity. Diagnostic specificity can be enhanced using emerging PET radiotracers, e.g., FLT and FET.

RECENT FINDINGS

Emerging research has shown higher dimensional analysis (radiomics and radiogenomics) of imaging data can yield information of the underlying genetic aberrations in lymphoma, which can aid in assessing real-time evolution of tumor. CT, PET/CT, MRI, and ultrasound accentuate the intrinsic qualities of lymphoma (e.g., FDG PET/CT for increased metabolic activity, FLT PET/CT for increased proliferation index, and DWI for increased cellularity) and play an essential role in its diagnosis and examination. Advanced radiogenomic analyses use radiomic parameters to deduce genetic variations of lymphoma, providing noninvasive, repeatable, and real-time surveillance of its genetic progression.

Primary bone lymphoma: pictorial essay

Primary bone lymphoma is a rare neoplasm that can initially present as local pain, a palpable mass, and pathologic fracture. It can also be discovered as an incidental finding on an imaging examination. It is defined as a bone marrow tumor with no involvement of other sites, lasting at least six months. The diagnosis is confirmed by biopsy and immunohistochemical analysis. Although the imaging characteristics are nonspecific, there are certain findings that, when correlated with clinical and epidemiological aspects, can increase the level of suspicion of primary bone lymphoma. The classic imaging aspect is a bone lesion with a soft-tissue component that preserves the cortical layer more than would be expected given the invasive nature of the lesion. Magnetic resonance imaging is the best imaging method to evaluate the extent of involvement of adjacent compartments, whereas computed tomography depicts the cortical layer in greater detail, as well as being an important tool for biopsy guidance. Other imaging modalities are also discussed, such as X-ray, ultrasound, bone scintigraphy, and positron emission tomography/computed tomography. The aim of this paper is to describe the most common findings obtained with the various imaging methods used in patients with a confirmed diagnosis of primary bone lymphoma.

Primary bone lymphoma: Clinical presentation and therapeutic considerations

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Primary lymphoma of bone is a rare entity with unspecific symptoms.

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Typical radiology is a large soft-tissue tumor around non-destructed bone.

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Treatment is based on systemic chemotherapy.

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Chemotherapy seems to produce a better outcome than radiotherapy alone.

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Positiv factors: age<60 y, solitary lesion, low LDH, favourable ECOG and IPI scores.

Background

Primary lymphoma of bone (PBL) is a rare entity. Due to unspecific clinical signs and equivocal radiographs diagnosis may be delayed. This retrospective report of 109 PBL cases demonstrates typical aspects of the lesion. Treatment and prognostic factors are evaluated.

Methods

Retrospectively patient records were reviewed. All patients were followed for evidence of local or distant recurrence. Overall survival (OS) was used as clinical outcome.

Results

The median age of the 109 patients was 62.8 years. The most common symptoms were pain (76%), swelling (29%), neurologic symptoms and pathological fracture (16% each). Mean duration of symptoms was 8 months (0–197 months).

19% of patients had indolent NHL subtypes, 72% aggressive NHL subtypes and 7% cases Hodgkin disease. Cyclophosphamid, doxorubicin, vincristine and prednisone (CHOP) or CHOP plus rituximab (RCHOP) were given in 88 (81%) of patients. Radiotherapy was delivered in 67 (61%) of cases. 51 (47%) patients received both. Surgical interventions were restricted to cases with complications as fractures.

The 5-year OS was 66%. The 5-year OS was 66%. In the subgroup of 78 patients with aggressive NHL subtype there was a highly significant benefit for chemotherapy or chemotherapy and radiation in comparison to no treatment or radiation alone. Raised LDH, age, IPI and ECOG performance were prognostic factors. In multivariate analysis, age and raised LDH levels only kept significance.

Conclusions

In our series of primary bone lymphoma, chemotherapy resulted in a better outcome than Radiotherapy alone. Long-term survival is based on the stage of the disease, favoring younger (<60 years) patients with solitary bone lesions, low level of LDH and favourable ECOG performance status and IPI scores.

Preliminary clinical assessment of dynamic carbon-11 methionine positron-emission tomography/computed tomography for the diagnosis of the pathologies in patients with musculoskeletal lesions: a prospective study

Background

This study prospectively assessed the diagnostic capacity of dynamic carbon-11 methionine (C-11 MET) positron-emission tomography (PET)/computed tomography for the diagnosis of pathologies in patients with primary unknown musculoskeletal lesions (MSLs). In total, 13 patients with MSLs underwent dynamic scans (5–10 [phase 1], 10–15 [phase 2], 15–20 [phase 3], 20–25 [phase 4], 25–30 [phase 5], and 30–35 [phase 6] min post-injection of C-11 MET). We statistically compared the maximum standardised uptake values (SUVmax) and corresponding retention index for dynamic scans (RI-SUV) for five benign MSLs (BMSLs), five primary malignant musculoskeletal tumours (PMMSTs), four metastatic musculoskeletal tumours (MMSTs), and three malignant lymphoma (ML) cases and explored their diagnostic capacities using receiver operating characteristic (ROC) curve analyses.

Results

SUVmax gradually decreased or remained similar with minimal fluctuations in all BMSL cases and four of five PMMST cases. In contrast, SUVmax increased over time in one case of PMMST and in all cases of MMST and ML. Significant differences were observed in SUVmax for all time phases and RI-SUV between BMSLs and MMSLs, in SUVmax for all time phases between PMMSTs and BMSLs, in SUVmax for all time phases and RI-SUV between non-PMMST-malignant tumours and BMSL, and in RI-SUV between non-PMMST-malignant tumours and PMMST. In ROC analyses, the areas under the curve yielded the highest values at 1.00 for differentiating most intergroup comparisons.

Conclusions

Dynamic C-11 MET PET scans have the potential to be good predictors of discriminating MSLs in patients with primary unknown MSLs in clinical practice.

Tibial tuberosity lesions

Lesions of the tibial tuberosity are very rare but often present a diagnostic dilemma due to their unusual location and appearances. Although some pathologies affecting this region are commonly seen elsewhere in the skeleton, they may have atypical imaging appearances and morphological characteristics when present at the tibial tuberosity. The present review describes the developmental stages of the tibial tuberosity, explaining why this area is prone to degenerative tractional changes and injury, and also highlights various pathologies including benign and malignant osseous lesions and trauma/degenerative related abnormalities.

Focal nodular marrow hyperplasia: Imaging features of 53 cases

OBJECTIVE

To describe the characteristic imaging features of focal nodular marrow hyperplasia (FNMH).

METHODS AND MATERIALS

Retrospective review of all patients with a diagnosis of FNMH between January 2007 and September 2019.

RESULTS

The study included 53 patients, 7 males and 46 females with a mean age of 58 years (range 12-95 years). All had MRI with conventional spin echo sequences showing a poorly defined round/oval lesion with mild T₁W iso/hyperintensity compared to skeletal muscle, low T₂W turbo spin echo (TSE) signal intensity (SI) compared to marrow fat and variable SI on STIR, but never associated with reactive marrow oedema. All 53 patients had follow-up MRI, with all lesions remaining stable or partially resolving. In-phase (IP) and out-of-phase (OP) chemical shift imaging (CSI) was obtained in 31 of these, with 28 (90.3%) showing >20% SI drop on the OP sequence, while 3 (9.7%) demonstrated <20% SI drop. CT was available in 26 cases, 17 (65.4%) showing mild medullary sclerosis. Single-photon emission computed tomography CT (SPECT-CT) was available in four cases and Flourodeoxyglucose positron emission tomography CT (FDG PET-CT) in 2, all showing increased uptake. Focal uptake was also seen in three of eight patients who had undergone whole body bone scintigraphy. Only one lesion was biopsied, confirming FNMH.

CONCLUSION

The imaging appearances of FNMH have been described on various modalities, particularly MRI with emphasis on the role of IP and OP CSI typically demonstrating >20% SI reduction. FNMH should be recognised and treated as a 'do not touch' lesion which does not require biopsy or prolonged follow-up.

ADVANCES IN KNOWLEDGE

We describe and clarify the imaging characteristics of FNMH on MRI, including CSI, CT and various nuclear medicine modalities. An imaging algorithm is suggested for allowing a non-invasive diagnosis.

Imaging of skull vault tumors in adults

The skull vault, formed by the flat bones of the skull, has a limited spectrum of disease that lies between the fields of neuro- and musculoskeletal radiology. Its unique abnormalities, as well as other ubiquitous ones, present particular features in this location. Moreover, some benign entities in this region may mimic malignancy if analyzed using classical bone-tumor criteria, and proper patient management requires being familiar with these presentations. This article is structured as a practical review offering a systematic diagnostic approach to focal calvarial lesions, broadly organized into four categories: (1) pseudolesions: arachnoid granulations, meningo-/encephaloceles, vascular canals, frontal hyperostosis, parietal thinning, parietal foramina, and sinus pericrani; (2) lytic: fibrous dysplasia, epidermal inclusion and dermoid cysts, eosinophilic granuloma, hemangioma, aneurysmal bone cyst, giant cell tumor, metastasis, and myeloma; (3) sclerotic: osteomas, osteosarcoma, and metastasis; (4) transdiploic: meningioma, hemangiopericytoma, lymphoma, and metastasis, along with other less common entities. Tips on the potential usefulness of functional imaging techniques such as MR dynamic susceptibility (T2*) perfusion, MR spectroscopy, diffusion-weighted imaging, and PET imaging are provided.

ABC-type diffuse large B-cell lymphoma presenting as rotator cuff tendinopathy: A diagnostic dilemma and review of the literature

Diffuse large B-cell lymphoma often presents with extranodal manifestations involving the musculoskeletal system. Shoulder pain is particularly worrisome for malignancy. Individuals presenting with refractory upper extremity complaints should undergo a prompt and thorough evaluation for cancer, as a delay in diagnosis can result in an unfavorable outcome.

Kaposi Sarcoma mimicking pedal osteomyelitis in a patient with HIV

Kaposi Sarcoma (KS) is an angio-proliferative mesenchymal neoplasm that typically affects the skin. In the setting of AIDS, it is usually disseminated, commonly involving noncutaneous sites like oral cavity, lymph nodes, pulmonary, and gastrointestinal systems. Musculoskeletal system involvement by KS is rare, and when encountered, it typically involves the axial skeleton (vertebrae, ribs, sternum, and pelvis) and/or maxillofacial bones. This report describes an unusual case of a 44-year old patient with HIV, who presented with a foot ulcer that fit the typical clinical features of osteomyelitis until MRI of the foot demonstrated atypical findings that challenged the original clinical diagnosis. This case highlights the role that advanced diagnostic imaging plays in the diagnosis of musculoskeletal Kaposi Sarcoma and serves as a reminder to radiologists to include Kaposi Sarcoma in the differential of multifocal osteolytic lesions in patients with HIV.

Beneficial effect of consolidative radiotherapy for patients with lymphoma and skeletal involvement

The objectives of this study were to analyze the clinical features of patients with bone involved lymphoma and identify the prognostic factors and to explore the optimized treatment strategy for bone involved lymphoma.A total of 1948 patients with lymphoma in our cancer center from September 2006 to October 2017 were retrospectively evaluated. Among these, 109 patients with skeletal involvement in lymphoma were enrolled. According to the pathologic subtypes, the patients were divided into 3 subgroups: classic Hodgkin lymphoma (cHL), B-cell non-Hodgkin lymphoma (B-NHL), and T-cell non-Hodgkin lymphoma (T-NHL). The clinical characteristics and overall survival (OS) of 3 groups of patients were reviewed, and the prognostic factors were analyzed.There were 9 (3 unifocal, 6 multifocal) patients with primary bone lymphoma. The 5-year OS of cHL, B-NHL, and T-NHL patients was 88.24%, 54.09%, and 61.58%, respectively. Advanced stage, elevated lactate dehydrogenase (LDH), age above 60, high International Prognostic Index score, and treatment without radiotherapy for the bone involved were significant poor prognostic factors for OS of all patients in univariate analysis. There was a trend toward better OS not only in limited-stage but also in advanced-stage patients with radiotherapy for the bone involved compared with the patients without radiotherapy. Elevated LDH level and age above 60 were the independent unfavorable prognostic factor in multivariate analysis.Elevated LDH level and age above 60 predict the poor prognosis of patients with bone involvement. The potential for long-term survival suggests that additional consolidative radiotherapy for the site of skeleton involvement may have a better chance of long-term success.

Spectrum of lytic lesions of the skull: a pictorial essay

Abstract

Lytic lesions of the skull include a wide range of diseases, ranging from benign conditions such as arachnoid granulations or vascular lacunae, to aggressive malignant lesions such as lymphomas or metastases. An early and correct characterisation of the nature of the lesion is, therefore, crucial, in order to achieve a fast and appropriate treatment option. In this review, we present the radiological appearance of the most frequent lytic lesions of the skull, describing findings from different imaging modalities (plain X-rays, CT and MRI), with particular attention to diagnostic clues and differential diagnoses.

Teaching Points

• Osteolytic skull lesions may be challenging to diagnose.

• Association of different imaging techniques may aid image interpretation.

• Clinical information and extensive knowledge of possible differential diagnoses is essential.

• Some osteolytic tumours, although benign, may present as locally aggressive lesions.

• Malignant lesions require accurate staging, followed by variable treatment approaches.

Diffuse-primary-B-cell lymphoma of the cranial vault presenting as stroke

A rare case of diffuse-primary-B-cell lymphoma was misdiagnosed on emergency computed tomography because of blurred findings and a sclerotic appearance of the right parietal bone. In spite of computed tomography, magnetic resonance imaging provided a higher diagnostic yield, revealing more extensive diploic alterations and indicating the involvement of all of the cranial vault compartments. Therefore, a histologic examination of the surgical specimen was conducted to reach a conclusive diagnosis.

Muscular sarcoidosis involving the chest and abdominal walls: case report with MR imaging

Sarcoidosis is an inflammatory disorder that is characterized by the presence of noncaseating granulomas in tissues, involving many organs and tissues. Extra-pulmonary, especially muscular sarcoidosis is a rare condition. The most common location of the muscular sarcoidosis is known to be the proximal muscles of the extremities; however, there have been no cases of diffuse involvement of the chest and abdominal wall muscles. Here, we report a rare muscular sarcoidosis with infiltrative pattern in the chest and abdominal wall muscles and describe the MR imaging findings that were mistaken as lymphoma at initial diagnosis. Although our case did not show characteristic MR findings of muscular sarcoidosis, clinicians or radiologists who are aware of these imaging features can perform early systemic survey for sarcoidosis. Also muscle biopsy is very important to confirm the sarcoidosis and distinguish it from other tumors.

MR Imaging of Atraumatic Muscle Disorders

Atraumatic disorders of skeletal muscles include congenital variants; inherited myopathies; acquired inflammatory, infectious, or ischemic disorders; neoplastic diseases; and conditions leading to muscle atrophy. These have overlapping appearances at magnetic resonance (MR) imaging and are challenging for the radiologist to differentiate. The authors organize muscle disorders into four MR imaging patterns: (a) abnormal anatomy with normal signal intensity, (b) edema/inflammation, (c) mass, and (d) atrophy, highlighting each of their key clinical and imaging findings. Anatomic muscle variants, while common, do not produce signal intensity alterations and therefore are easily overlooked. Muscle edema is the most common pattern but is nonspecific, with a broad differential diagnosis. Autoimmune, paraneoplastic, and drug-induced myositis tend to be symmetric, whereas infection, radiation-induced injury, and myonecrosis are focal asymmetric processes. Architectural distortion in the setting of muscle edema suggests one of these latter processes. Intramuscular masses include primary neoplasms, metastases, and several benign masslike lesions that simulate malignancy. Some lesions, such as lipomas, low-flow vascular malformations, fibromatoses, and subacute hematomas, are distinctive, but many intramuscular masses ultimately require a biopsy for definitive diagnosis. Atrophy is the irreversible end result of any muscle disease of sufficient severity and is the dominant finding in disorders such as the muscular dystrophies, denervation myopathy, and sarcopenia. This imaging-based classification, in correlation with clinical and laboratory data, will aid the radiologist in interpreting MR imaging findings in patients with atraumatic muscle disorders. ^©RSNA, 2018.

Primary skeletal muscle lymphoma: A case report

Primary lymphomas of the bone or skeletal muscle are rare. Three mechanisms of lymphomatous involvement of the muscle have been described, namely direct invasion from adjacent involved lymph nodes or bone, metastatic spread and, least commonly, primary muscle lymphoma. We herein present a rare case of primary mucle non-Hodgkin lymphoma with a description if the associated clinicopathological findings and a review of the relevant literature. A 41-year-old female patient was referred to our hospital with a painful mass in the right lower extremity. Following resection and histopathological examination, a diffuse large B-cell lymphoma originating from the muscle with cutaneous and subcutanenous infiltration was diagnosed. The patient received chemotherapy with six cycles of cyclophosphamide, hydroxydaunomycin, oncovin and prednisone (CHOP regimen) and a complete radiological response was achieved after six cycles of treatment.

Spectrum of CT Findings in Thoracic Extranodal Non-Hodgkin Lymphoma

Non-Hodgkin lymphoma (NHL) frequently manifests in extranodal structures in the chest, often in the form of secondary involvement but occasionally as primary disease. Because staging and treatment are affected by the presence of extranodal disease at imaging, radiologists' interpretation and management of suspicious findings are critical to patient care. Unfortunately, owing to considerable imaging overlap with other diseases, primary extranodal lymphoma is difficult to diagnose with imaging alone. Radiologists should have a heightened degree of suspicion in patients at risk (including patients with immune compromise, autoimmune diseases, or a history of stem cell or solid organ transplant) or with particular imaging appearances (including the vertebral wraparound sign, nonresolving consolidation, an infiltrative soft-tissue mass, and lesions demonstrating vascular encasement without invasion). For patients with known NHL, positron emission tomography/computed tomography (PET/CT) using fluorine 18 (¹⁸F)-labeled fluorodeoxyglucose (FDG) is now preferred for routine staging in most cases. CT remains heavily used, and identification of subtle extranodal involvement with CT can be improved with use of intravenous contrast material and careful review of multiplanar images. Pericardial effusion, pleural soft tissue (even when mild), mass-like consolidation, perilymphatic nodularity, and new lytic bone lesions are particularly suggestive of secondary involvement in a patient with known NHL. Magnetic resonance imaging is a helpful problem-solving tool when equivocal findings would change staging and treatment. This comprehensive review illustrates the spectrum of CT manifestations of extranodal NHL in the chest, including the pleura, lung, airways, heart, pericardium, esophagus, chest wall, and breast. ^©RSNA, 2017.

The great mimicker at thoracolumbar spine: Non-Hodgkin's lymphoma

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Non-Hodgkin’s lymphoma’s vertebral involvement is quite common.

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Diagnosis of the non-Hodgkin’s lymphomas that are localized in thoracolumbar spine often is missed or is delayed.

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It was purposed to report two cases with non-Hodgkin’s lymphoma in thoracolumbar spine with different presentation.

Purpose

To report two cases with Non-Hodgkin’s Lymphoma (NHL) in thoracolumbar spine with very different presentation.

Methods

Case 1; An 84-year-old female patient was admitted to our emergency clinic with paraparesis in both lower extremities. Magnetic resonance imaging (MRI) revealed an epidural mass at the level of the T12 vertebrae. She was operated immediately with wide laminectomy and posterior instrumentation because of the paraparesis of both lower extremities. Case 2; An 70-year-old female patient was admitted to our clinic with thoracolumbar back pain. There was a T12 vertebra compression fracture view in the X-ray imaging. MRI revealed multiple infiltrations in medullar canale at thoracolumbar spine with lytic lesion. She underwent eight cycles of chemotherapy.

Results

Multiple bone involvement was detected in both cases in PET-CT (Positron emission tomography–computed tomography) scans. Additionally it was found that there were nodal involvements accompanying these involvements in case 1. Because radiological examinations were not spesific enough to diagnose, it was necessary to perform a biopsy. The histopathological diagnosis of these patients revealed diffuse large B cell non-Hodgkin’s lymphoma.

Conclusions

Diagnosis of the non-Hodgkin’s lymphomas that are localized in thoracolumbar spine is often missed or delayed due to lack of specific findings and presence similarities to other diseases. Diagnosis is made by histopathologic examination. Although the main treatment is chemotherapy for these patients, surgery is necessary for patients with neurological deficite.

Skeletal Muscle Involvement in B-Cell Lymphoma: Two Cases Illustrating the Contribution of Imaging to a Clinically Unsuspected Diagnosis

Skeletal muscle lymphoma is rare, comprising only a very small subset of lymphoma cases. There are characteristic imaging features which, if recognized, can prevent delay in diagnosis and treatment, particularly when not suspected clinically. Herein, we report two cases of skeletal muscle lymphoma with nearly identical imaging features; the first is an example of primary muscle lymphoma in a 17-year-old boy with back and thigh pain, and the second represents lymphoma recurrence in a 55-year-old man with HIV. Characteristic features seen on MRI were key in raising suspicion for the disease and helped prevent a delay in pathologic diagnosis.

Distal appendicular skeletal involvement of diffuse large B-cell lymphoma on technetium-99m methylenediphosphonate bone scintigraphy and 18F-fluorodeoxyglucose positron emission tomography/computed tomography: a case report

BACKGROUND

We report a case of a patient with appendicular bone involvement of diffuse large B-cell lymphoma visualized by whole-body technetium-99m methylenediphosphonate bone scintigraphy (bone scan) and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography.

CASE PRESENTATION

A 73-year-old Asian man who had gingival swelling of the labial area of the left maxillary lateral incisor presented to our institution. Positron emission tomography/computed tomography demonstrated hypermetabolic lesions with maximum standardized uptake values of 12.15 in the left testis, 1.92 in the skin of the right chest, and 2.88 in the left ulna and third metatarsal bone. A bone scan showed multiple uptakes in the left ulna, hand, both tibiae, and the left foot. We diagnosed the tumor as diffuse large B-cell lymphoma by excision. Magnetic resonance imaging showed enhanced signaling of lesions with soft tissue edema in the olecranon of the left ulna, the third metacarpal bone of the left hand, and the third metatarsal bone of the left foot. Magnetic resonance imaging findings prompted a diagnosis of lymphoma. Eight cycles of chemotherapy plus external radiotherapy targeted to the involved bone sites were given for 5 months. Follow-up positron emission tomography/computed tomography and bone scanning revealed the disappearance of hypermetabolism and decreased uptake in lesions compared with the previous images. Laboratory data were also all within the normal limits after chemotherapy.

CONCLUSIONS

This report highlights that appendicular bone involvement of diffuse large B-cell lymphoma can be detected on whole-body bone scans and by positron emission tomography/computed tomography.

Case of polyostotic primary bone lymphoma successfully treated with immunochemotherapy and consolidation radiotherapy

A 47-year-old woman presented with symptoms of sharp pain over the left anterior thigh with radiation from the groin to the knee. She subsequently developed numbness in that region and reduced motor strength in extensors of the left knee. Plain radiography of the spine and knee was normal. An MRI of the spine revealed an irregular extramedullary mass with intradural and extradural components, extending from the L3 to L5 vertebrae. She underwent a laminectomy and posterior spinal decompression based on a working diagnosis of nerve sheath tumour. Histopathology revealed a primary bone lymphoma. A positron emission tomography CT (PET-CT) performed as part of the staging workup revealed fluorodeoxyglucose avid lesions in the spine and left femur. She received immunochemotherapy (Rituximab-Cyclophosphamide, Hydroxydaunorubicin, Oncovin and Prednisone) for eight cycles with an interim PET-CT revealing complete response. Subsequently, she received consolidation radiotherapy, 36 Gy in 20 fractions over 4 weeks to both lesions. She is now disease-free on follow-up for the past 1 year.

Utility of F-18 FDG PET/CT on the evaluation of primary bone lymphoma

PURPOSE

Primary bone lymphoma (PBL) is a rare type of malignant lymphoma. Few data have been reported regarding the utility of F-18 FDG PET/CT in this disease. The aim of this study was to assess the role of F-18 FDG PET/CT in the diagnosis and therapeutic effect evaluation of PBL.

MATERIALS AND METHODS

A total of 19 consecutive patients with PBL were enrolled. Whole-body PET/CT scan was performed for all patients. The diagnosis of PBL was established by histopathology and immunohistochemistry.

RESULTS

F-18 FDG PET/CT was positive in 94.7% (18/19) of patients. Uptake of FDG in lesions was intense with SUVmax of 15.14 ± 11.82. Multiple involved lesions were found in 47.4% (9/19) patients, while 52.6% presented with a single involved lesion. Based on the lesions, PET detected 98.9% (87/88) lesions. Among them, 71.6% (63/88) lesions were found to be located in axial skeleton and 28.4% (25/88) in the extremity skeleton. FDG PET/CT also found the lesions infiltrate to the surrounding soft tissue in 84.2% (16/19) patients. On the syn-modality CT, the bone destruction was noted in 43.2% (38/88) of the lesions, of which 50.0% lesions presented as slight change in bone density and 50.0% as severe change. The diagnostic sensitivity of PET was much higher than that of CT (98.9% vs. 43.2%, P=0.000). PET/CT was performed for evaluation of treatment response in 13 patients. In 12 patients with complete response(CR), PET/CT found the 25 lesions were F-18 FDG fully resoluted after treatment, however, bone destruction was still presented in 72.0% (18/25) lesions.

CONCLUSIONS

The present study suggests that F-18 FDG PET/CT was a sensitive imaging modality for diagnosis and treatment response evaluation of PBL.

An Unusual MRI Appearance of Osseous Metastases

Bone metastases can present in a wide variety of appearances across all imaging modalities. We present a unique appearance of a distal femoral metastasis in a patient who initially complained of knee pain. The radiographic and CT findings were initially suspicious for calcium pyrophosphate deposition (CPPD) arthropathy; however, an MRI demonstrated multiple lesions with a lamellated appearance confirmed on biopsy to be metastatic disease. This unusual lamellated appearance has not been previously described. We present this case to help distinguish this entity radiographically and better classify this finding as a manifestation of metastatic disease.