Discussion
IMT is one of the rare low-to-intermediate grade sarcomas. Initially it
was thought to be an inflammatory response to various stimuli, but
recent studies have proved IMT to be neoplastic and can recur locally
and metastasize (7). It has also been suggested that trauma, surgery,
autoimmune etiologies, inflammation, and infections such as Epstein-Barr
virus or human herpes virus could result in the development of IMT (8).
IMT was first described in the lungs but later was also found in other
sites such as the orbit, spleen, genitourinary tract, mesentery,
cardioesophageal junction, breast, central nervous system, and larynx.
The larynx has been a very rare site for involvement in IMT (9).
Children with IMT may exhibit symptoms of chronic inflammation as a
low-grade fever, weight loss, anemia, thrombocytosis, polyclonal
hyper-gammaglobulinemia, and elevated sedimentation rate. Several cases
are asymptomatic and are detected only incidentally on imaging studies.
Among patients with end-obronchial lesions, symptoms of bronchial
irritation such as cough and hemoptysis may be accompanied by chest pain
(10).
In our case, chest x-ray, history of weight loss and occurrence of
intermittent fever and hemoptysis, beside endemic status, made us
suspicious to infectious process like tuberculosis or echinococcosis.
Because of the negative staining of BAL sample and laboratory data, we
thought about the non-infectious process like malignancies because of
weight loss. Despite of doing bronchoscopy and HRCT, the diagnosis was
last after histopathological assessment. According to previous studies,
there are only 26 published cases of pediatric pulmonary IMT (the age
between 3 to 13 years), even though the real incidence is presumed to be
higher (3, 11). Peripheral lung lesions appear to be more frequent than
central and endobronchial tumors that may be present about in 10% of
the cases resulting in bronchial obstruction and atelectasis (12).
IMT can be sometimes diagnosed as incidental finding on a routine CXR
(13). In all previous cases, at the time of presentation, patients had
fever, respiratory distress, arthralgia, clubbing, night sweat,
vomiting, and hemoptysis and at the onset, fever and cough were the
commonest symptoms (3). There has been an ongoing controversy whether an
IMT is a reactive lesion or a true neoplasm (14). Although its incidence
is fairly scarce, the existing literature clearly defines its relative
similarities in terms of clinico-pathological and radiological findings
and almost uniformly favors surgical resection as a mainstay for the
most efficient management strategy. The recurrence rate remains low and
a 10-year survival rate is around 80% (15).
Treatment is primarily a complete but conservative surgical excision.
This approach is necessary to prevent recurrence (16, 17). An
appropriate histologic assessment should be obtained before the surgery
(needle biopsy by bronchoscopy), in order to avoid an unnecessarily
procedure (17).