Giant Cell Containing Lesions of Bone

Reactive

• Brown tumor of hyperparathyroidism
• Hemophiliac pseudotumor

Benign

• Giant cell reparative granuloma
• Non-ossifying fibroma
• Giant cell tumor
• Aneurysmal bone cyst
• Chondroblastoma
• Chondromyxoid fibroma
• Langerhans cell histiocytosis

Malignant

• Osteosarcoma
• Clear cell chondrosarcoma
• Metastatic carcinoma
• Malignant fibrous histiocytoma
• Solitary fibrous tumor metastasis

ILAR Classification of Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is an umbrella term for a group of abnormalities characterized by chronic articular inflammation and association with HLA alleles. The International League Against Rheumatism (ILAR) has classified JIA into seven subtypes, including an unclassifiable group. These include:

• Systemic arthritis: Arthritis in one or more joints with or preceded by fever of at least 2 weeks' duration documented to be daily for at least 3 days, and accompanied by one or more of: evanescent erythematous rash, lymphadenopathy, hepatomegalyor splenomegaly, or both, serositis
• Oligoarthritis: Arthritis in 4 or fewer joints in the first 6 months. Subtypes include persistent (no more than 4 joints throughout the course of the disease) and extended (more than 4 joints after the first 6 months).
• Polyarthritis, RF negative: Arthritis affecting 5 or more joints in the first 6 months of disease. RF is negative
• Polyarthritis, RF positive: Arthritis affecting 5 or more joints in the first 6 months of disease. Two or more tests for RF, conducted at least 3 months apart during the first 6 months, are positive. Considered the pediatric version of adult rheumatoid arthritis.
• Psoriatic: Arthritis plus psoriasis OR Arthritis plus at least two of the following: dactylitis, nail pitting or onycholysis, psoriasis in a first-degree relative.
• Enthesis-related: Arthritis plus enthesitis OR Arthritis or enthesitis, plus at least two of the following: presence of or a history of sacroiliac joint tenderness and/or inflammatory lumbosacral pain‡, presence of HLA-B27 antigen, onset of arthritis in a male over 6 years of age, acute (symptomatic) anterior uveitis, history of AS, ERA, sacroiliitis with IBD, reactive arthritis, or acute anterior uveitis in a first-degree relative
• Unclassified: Arthritis that fulfills criteria in none of the above categories, or fulfills criteria in two or more of the above categories

References

Petty RE, Southwood TR, Baum J, Bhettay E, Glass DN, Manners P, Maldonado-Cocco J, Suarez-Almazor M, Orozco-Alcala J, Prieur AM. Revision of the proposed classification criteria for juvenile idiopathic arthritis: Durban, 1997. J Rheumatol. 1998 Oct;25(10):1991-4.

Subcutaneous Panniculitis-Like T-Cell Lymphoma

Subcutaneous panniculitis-like T-cell lymphoma is a rare cutaneous T-cell lymphoma (SPTCL) that is characterized by subcutaneous nodules and plaques. The similarity of presentation to that of panniculitis is the reason for the long name. The disease most commonly involves the legs, but can also affect the trunk. It can be differentiated from the cutaneous T-cell lymphomas (e.g., mycosis fungoides and Sézary syndrome) by the fact that the former are cutaneous, and SPTCL is subcutaneous.

References

Levine BD, Seeger LL, James AW, Motamedi K. Subcutaneous panniculitis-like T-cell lymphoma: MRI features and literature review. Skeletal Radiol. 2014 Sep;43(9):1307-11.

Costochondritis

Costochondritis, as its implies, is a nonspecific term for inflammation of the costal cartilage. The problem with this definition is that it implies a non-specific process, where inflammation can be caused by any number of pathological processes, including trauma, infection, or radiation.

The clinical entity of costochondritis, on the other hand, has specific features:

• Self-limited
• Usually multiple affected levels
• Can occur at the costochondral junction or at the chondrosternal joints
• No swelling or induration on physical examination
• Pain that is reproduced by palpation and may radiate on the chest wall

This definition differentiates costochondritis from the much rarer Tietze syndrome (TS). In TS, the inflammatory process causes visible enlargement of the costochondral junction(s) and is most commonly isolated to a single rib (usually the 2nd, but can also involve the 3rd rib). TS can be caused by infectious, rheumatologic, and neoplastic processes. The infection is usually associated with trauma (e.g., stab wounds, iatrogenic) or with intravenous drug use.

Costochondritis is relatively common, and can be seen is as many as 14% of adolescents and 13 to 36% of adults with chest pain.

References

Proulx AM, Zryd TW. Costochondritis: diagnosis and treatment. Am Fam Physician. 2009 15;80(6):617-20.

Waldenström macroglobulinemia: Imaging Checklist

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma that is associated with an immunoglobulin M (IgM) monoclonal protein (M-protein). To establish the diagnosis of WM, it is necessary to demonstrate IgM monoclonal protein in the serum, along with histologic evidence of lymphoplasmacytic cells in the bone marrow. There is a similar spectrum of disease to that seen multiple myeloma (MGUS, smoldering myeloma, and frank myltiple myeloma) in WM: IgM monoclonal gammopathy of undetermined significance, smoldering macroglobulinemia, and WM.

WM is more common in men and in whites. The most common presenting symptom is fatigue related to a normochromic or normocytic anemia. Patients can also have peripheral neuropathy. Hyperviscosity syndrome, which includes epistaxis, gingival bleeding, and retinal hemorrhage is related to high plasma IgM concentrations and is becoming less common due to earlier diagnosis. It is rarely seen in patients with IgM concentration of <4,000 mg/dL.

The checklist for reviewing images in these patients includes clinical features, complications of the disease, and potential mimickers. These include:

• Lymph nodes: The majority of patients have adenopathy on FDG-PET and CT.
• Bone marrow: Almost half of patients show diffuse increased uptake on PET, and about 90% will show marrow signal changes on MRI (diffuse in more than half). This can be due to marrow infiltration or hyperplasia due to anemia.
• Spleen size: Between 10-20% of patients will have splenomegaly on imaging
• Liver size: Hepatomegaly can be seen in patients, but the prevalence on imaging has not been reported.
• Viscera: Between 10-20% of patients will have visceral or extra-nodal sites of involvement on imaging.
• Venous patency: To assess for thrombosis due to hyperviscosity from high IgM protein
• Vessel walls: To assess for immune complex vasculitis due to IgM protein
• Presence of hemorrhage: Due to low levels of von Willebrand factor
• Central nervous system: To assess for presence of Bing-Neel syndrome, which is perivascular infiltration of small lymphocytes, lymphoplasmacytoid cells, and plasma cells in the brain parenchyma and/or spine.
• Amyloidosis: Imaging features of amyloidosis should be sought, since it can also present with an IgM monoclonal protein and neuropathy (particularly if the light-chain isotype is lambda).

WM can be difficult to differentiate from marginal zone lymphoma. MYD88 mutation L265P is more commonly seen in WM (67% of cases), and less commonly in splenic marginal zone lymphoma (4%) and mucosa-associated lymphatic tissue lymphoma (7%).

Because the M-protein of patients with WM is almost always IgM, a broad differential should be considered for lucent bone lesions (the M-protein of multiple myeloma is usually IgG, followed by IgA and IgD, with IgM myeloma making up about 1% of cases). The same can be said for sclerotic bone lesions with or without peripheral neuropathy (the M-protein of POEMS is usually IgG and IgA, with IgM POEMS being very rare). However, this information is not always available when interpreting initial staging studies for patients with newly diagnosed plasma cell dyscrasia.

References

• Banwait R, O'Regan K, Campigotto F, Harris B, Yarar D, Bagshaw M, Leleu X, Leduc R, Ramaiya N, Weller E, Ghobrial IM. The role of 18F-FDG PET/CT imaging in Waldenstrom macroglobulinemia. Am J Hematol. 2011 Jul;86(7):567-72.
• Gertz MA. Waldenström macroglobulinemia: 2013 update on diagnosis, risk stratification, and management. Am J Hematol. 2013 Aug;88(8):703-11.
• Moulopoulos LA, Dimopoulos MA, Varma DG, Manning JT, Johnston DA, Leeds NE, Libshitz HI. Waldenström macroglobulinemia: MR imaging of the spine and CT of the abdomen and pelvis. Radiology. 1993 Sep;188(3):669-73.

Radiographic Appearance of the Ascenda® 8780 and 8781 Intrathecal Catheters

The Ascenda® 8780 and 8781 intrathecal catheters are 3T MR conditional catheters and have a metallic marker in their catheter connectors that has the potential to be confused for a foreign body (it looked like a needle to me).

The metallic piece is inside the catheter connector. The connector is placed between the pump and spinal segments of the catheter and gives the user an audible and tactile confirmation of secure connection of the catheter segments.

A linear metallic object that is contiguous with the catheters on both views can help differentiate this from a retained foreign object.

The bottom image is from the Ascenda Manual

References

Ascenda Manuals and Technical Resources. Medtronic.

Sarcoid-Like Reaction in Oncology

Sarcoid is thought to develop in predisposed individuals by a cross-reaction to tumor, bacterial, viral, or inorganic antigens or immunogenes. Patients respond by forming noncaseating granulomas, which are most commonly intrathoracic. Sarcoid-like reaction (SLR) refers to the development of noncaseating granulomas in patients who do not fulfill the criteria for systemic sarcoidosis.

In oncological patients, SLR most commonly occurs in the lymph nodes draining a malignant tumor, but can also be observed in the organ of tumor origin and distant tissues. It develops after antineoplastic treatment with biologic modifiers (e.g., interferon and interleukin-2), single or combination chemotherapy agents, or even after surgery without chemotherapy.

The patient above has a history of melanoma of the left lower extremity with recurrent ipsi- and contra-lateral inguinal nodal involvement that has been treated with surgery (most recently 8 months ago) and chemotherapy in the remote past (cisplatin, vinblastine, and dacarbazine). The PET from 3 months ago (left panel) was clear. The new PET (right panel) shows new supraclavicular (red arrow), intra-thoracic (yellow arrows), and upper abdominal (blue arrow) adenopathy. The lymph nodes are highly FDG-avid and most prominent in the chest, where we see the symmetric hilar and mediastinal adenopathy typical of sarcoid and would be atypical for nodal involvement from lower extremity melanoma. It is important to keep SLR in mind in order to avoid over-calling disease progression. This can be more problematic in cases of intrathoracic neoplasms that would be expected to recur in the chest and involve hilar and mediastinal lymph nodes. Symmetrical hilar involvement can be a helpful hint in these cases.

References

• Inoue K, Goto R, Shimomura H, Fukuda H. FDG-PET/CT of sarcoidosis and sarcoid reactions following antineoplastic treatment. Springerplus. 2013 Dec;2(1):113.
• Tchernev G, Tana C, Schiavone C, Cardoso JC, Ananiev J, Wollina U. Sarcoidosis vs. Sarcoid-like reactions: The Two Sides of the same Coin? Wien Med Wochenschr. 2014 Jul;164(13-14):247-259.