Discussion
Pancreatic malignancy is the seventh most important cause of cancer morbidities globally. In 2018, 459,000 new patients reported with this disease [11]. In future, it is predicted to outstrip breast cancer in European countries as the third fore-most cause of cancer mortality [12]. Frequent etiological factors include obesity, nicotine exposure and elevated blood glucose levels [13,14]. It is perturbing for the patients diagnosed with pancreatic mass and they are mostly worried about the type of lesion which makes it essential to counsel appropriately and conduct rapid medical examination to conclude the final diagnosis.
Inflammatory pseudotumor is a title devised by Umiker and Iverson in 1954 due to overlapping symptomatic and radiological findings with pancreatic malignancy [15]. It is a benign, unusual entity which tends to involve all locations in the body but most frequently present in orbit and the lung. Inflammatory pseudotumors may be solitary or multitudinous with a blend of neutrophils and lymphocytes along with an uneven extent of fibrosis, myofibroblastic spindles, necrosis, and formation of granulomas [16-18].
ITP is known to be associated with autoimmune diseases, trauma and fibrosarcoma [19-21]. Other conditions such as IgG4 associated sclerosing disease where T-cell and IgG4 positive plasma cells attack multiple tissues. The manifestations include autoimmune pancreatitis, cholecystitis, tubulointerstitial nephritis, IPT, prostatitis, interstitial pneumonia and sclerosing cholangitis along with lymphadenopathy. Few patients have reported IgG4-related IPTs in the absence of autoimmune pancreatitis [22, 23].
IgG4-related disease presents as a tumor like swelling involving the organs it affects. The type 1 form of IgG4-related disease depicts a type of autoimmune pancreatitis. Patients frequently show up with an acutely developing mass, painless obstructive jaundice, and diffuse organomegaly. Such a presentation can be misunderstood for pancreatic cancer [24]. IgG4-related disease has a criteria of a serum IgG4 level > 135 mg/dL with around 40% of IgG+ plasma cells being IgG4+ (>10 cells/high-power field of biopsy sample). The following criterion is valuable, yet not adequately sensitive to diagnose type 1 IgG4-related autoimmune pancreatitis [25].
An international agreement was set up by the International Association of Pancreatology regarding the differential diagnosis of the two particular types of autoimmune pancreatitis (types 1 and 2). This can be differentiated on the basis of 5 criteria: (1) imaging changes in the pancreatic parenchyma and duct; (2) serology (for IgG4 and IgG antinuclear antibodies); (3) extrapancreatic involvement; (4) histology; and (5) response to corticosteroid therapy [26]. Radiological evaluation plays a crucial role in closely studying and identifying these lesions. However, the histopathological review is thought to be a much-needed step in landing on a definitive diagnosis [27]. CT scans might show a variable appearance of such inflammatory tumors, from hypoattenuated to isoattenuated depending on the muscle and few calcifications might be there in the liver, pancreas, or stomach pseudotumors. MRI images can likely differ; after the introduction of the contrast heterogeneous enhancement is seen. However, this still cannot differentiate these lesions from a true pancreatic carcinoma [19].
The definitive diagnosis of these lesions depends on the histopathological outcomes; with some specimens being attained post-surgical resection. This accounts for around 5–10% of the pancreatectomies. Surgical resection of the tumor is believed to be therapeutic despite the chances of possible morbidity and post-surgical complications. Some data indicate corticosteroids, nonsteroidal anti-inflammatory drugs, and thalidomide to have curative role and curtail the tumor burden [27, 21]. Recurrence rate is calculated to be around 18–40% [27]. Such recurrent lesions can be associated with local invasion. Resection of such lesions is indicated since they might possess a malignant transformation potential [21]. Literature suggests few occurrences of spontaneous regression [27,21].
IPTs are a rarity and a frequent incidental finding during routine radiological examination. They can also be encountered while investigating for non-specific clinical features or a detected mass from an unknown source. Definite diagnosis depends on the radiological and histological assessment that can be attained post-surgical resection or biopsy. Surgical resection is the first line of treatment if the diagnosis is not clear or was not previously done and it is curative in most cases. Surgical resection is the first line of treatment in case the diagnosis is unclear or wasn’t done in the first place. Surgical resection is curative in most cases.