IMTs are rare, distinctive lesions with an unclear etiology that were first described by Dr. H. Brunn in 1939 4. Grossly, IMTs may be firm, fleshy, or gelatinous, with a white or tan cut surface2. They typically occur in children and young adults and predominantly affect the lungs as only 5% of IMTs occur in extrapulmonary locations. Notably, such extrapulmonary lesions may occur in the head/neck, respiratory tract, intra-abdomen, extremities, and uterus2. The clinical presentation of IMTs is related to the location of the lesion and its affected organs because, for e.g., while patients with intra-abdominal tumors present with intermittent pain, abdominal distension, weight loss, malaise, anorexia, and vomiting5. In our patient, IMTs had affected the terminal ileum and caused an obstruction that mimicked ruptured appendicitis, which necessitated additional caution and improvisation during surgery due to the presence of unusual intra-operative findings.
Although CFTs are mainly seen in the gastrointestinal tract, they are also found in several organ systems. Even though most CFT lesions are solitary, multiple CFTs have also been reported, as seen in our patient. All CFTs were removed during laparoscopy, even though they were relatively benign. The coexistence of IMTs and CFTs was first reported in 1999, and thus, CFTs were hypothesized to be the sclerosing end stage of IMTs6. Additionally, Tomassen et al have reported that these two tumor types share a DNA methylation profile7, thereby supporting the theory that CFTs may be the end stage of IMTs. However, others consider them to be distinct entities based on histological findings, for e.g., while IMTs are positive for anaplastic lymphoma kinase, CFTs are negative. Further, IMTs stain positive for muscle-specific actin, smooth muscle actin, desmin, and vimentin, whereas CFTs are negative for all these molecules.
IMTs are classified as an intermediate neoplasm in the World Health Organization classification of soft tissue tumors due to their tendency to recur. In contrast, although CFTs are generally benign, case descriptions of familial occurrence have been reported8. The current treatment of choice for IMTs and CFTs is complete surgical resection5,9, and alternative treatment strategies, such as chemotherapy, radiotherapy, or immunomodulation drugs remain controversial as they have shown inconsistent results5. Further, IMT recurrence is determined by primary lesion site and ranges from 2% for lung lesions to 25–37% for extrapulmonary lesions1,10 with low incidence (5%) of distant metastases, with common sites being the lungs and brain. As major risk factors for recurrence are incomplete surgical resection, ALK negativity, and p53 positivity11, long-term clinical and radiological follow-up is recommended.