How pseudo is an inflammatory pseudotumor?

Abstract

Inflammatory pseudotumor (IPT) is a rare lesion of unclear etiology reported in various organs. Although mostly benign, these tumors may pose a therapeutic challenge in cases of recurrence. We report the case of a young male who presented with a clinical and radiological picture suggestive of a malignancy in the thorax and upon evaluation was noted to have IPT of the lung. Complete surgical resection was done with no evidence of tumor recurrence. We review the literature and discern the epidemiological, clinical, pathophysiological and management aspects of IPTs.

A case of inflammatory pseudotumor of the lung presenting as polymyalgia rheumatica

“…Inflammatory pseudotumors are rare lesions best described as well‐circumscribed, non‐encapsulated masses of unregulated cellular growth. These lesions are generally not uniform and may contain elements of inflammation, hemorrhagic features, calcification and rarely, cavitation . Inflammatory pseudotumors have been reported in a variety of organ systems to include the central nervous system, liver, spleen, salivary glands, soft tissue and skin as well as in the lung .…”

“…Etiology of these lesions remains unclear; however, case reports suggest that inflammatory pseudotumors represent an exaggerated immunologic response and possibly impaired T‐cell function . Many believe that these lesions could be triggered by the body's reaction to a viral or foreign antigen reaction such as to minor trauma, mycobacteria, Epstein‐Barr Virus, Actinomyces, Nocardia, mycoplasma, or Herpes Simplex Virus . They have also been associated with malignancies …”

Laryngeal paralysis associated with a muscle pseudotumour in a young dog

“…Several synonyms exist in human literature (Knight et al, 2009), contributing to confusion surrounding the comprehension of this uncommon disease. This condition has been reported in humans and animals (horses, dogs and cats) with no particular age or sex incidence and with different localisations (Cooper and Valentine, 2002;van der Woerdt, 2008;Loderstedt et al, 2010;Gude et al, 2011;Segawa et al, 2014). In humans, clinical or subclinical muscle injury and denervation injury have been proposed as a possible aetiology, however such correlations have not been proved (Cooper and Valentine, 2002; The Armed Forces Institute of Pathology, 2007;Knight et al, 2009).…”

“…They have been reported in humans (Gude et al, 2011;Segawa et al, 2014) and occasionally in animals (Cooper and Valentine, 2002;van der Woerdt, 2008;Knight et al, 2009;Loderstedt et al, 2010). Aetiology of muscle pseudotumours remains unknown, although several hypotheses have been postulated.…”

Inflammatory Myofibroblastic Tumor

“…Often patients are asymptomatic although persistent cough, pulmonary infections or thoracic discomfort may be present. General symptoms such as weight loss, fever and fatigue are also reported [5]. Histologically IMT is considered as a benign lesion consisting of myofibroblastic spindle cells with a prominent inflammatory infiltrate composed of plasma cells and lymphocytes.…”