Epithelioid inflammatory myofibroblastic sarcoma: a clinicopathological, immunohistochemical and molecular cytogenetic analysis of five additional cases and review of the literature

Abstract

BackgroundTo explore the clinical characteristics and pathological features of epithelioid inflammatory myofibroblastic sarcoma (EIMS) with emphasis on the diagnostic spectrum.MethodsThe clinical data and histological features in 5 additional cases of EIMS were retrospectively reviewed. Immunohistochemical study and interphase fluorescence in situ hybridization (FISH) analysis were carried out.ResultsThere were 2 males and 3 females with age at presentation ranging from 15 to 58 years (mean, 37 years). All 5 tumors were intra-abdominal with 2 arising in the mesentery and 1 each in the omentum, rectum and transverse colon. The tumor size ranged from 5 to 20 cm in maximum diameter (mean, 10.7 cm). Histologically, all 5 tumors were composed predominantly of large epithelioid cells possessing vesicular nuclei, prominent nucleoli, and amphophilic cytoplasm. Mitotic figures were easily identified (mean, 20/10HPF). Tumor cells were arranged in clusters or sheets embedded in a myxoid stroma containing prominent neutrophils. A minor component of spindle cells was present in focal areas. By immunohistochemistry, all 5 cases were positive for anaplastic lymphoma kinase (ALK) with a nuclear membrane pattern in 4 and cytoplasmic staining with perinuclear accentuation in 1. Besides ALK, tumor cells stained variably for desmin (4/5), alpha smooth muscle actin (2/5), muscle-specific actin (1/2) and pan-cytokeratin (1/4). FISH analysis demonstrated the presence of ALK rearrangement in all 5 cases. Of 5 patients, 3 developed local recurrence, 1 died of disease 8 months after surgery.ConclusionEIMS represents a highly aggressive variant of inflammatory myofibroblastic tumor characterized by epithelioid morphology, prominent neutrophilic infiltrate, and nuclear membrane staining of ALK with ALK rearrangement. As patients with ALK-rearrangement tumors may benefit from targeted therapy, accurate diagnosis of EIMS is very important. Familiar with the characteristic features of EIMS will help pathologists avoid misdiagnosing the tumor as other malignancies.

Crizotinib in ALK+ inflammatory myofibroblastic tumors—Current experience and future perspectives

“…Although spontaneous regression of IMT has been documented, complete resection is considered to be the treatment of choice whenever possible . Incomplete resection is associated with a high recurrence rate, and outcome of second‐line treatment options including nonsteroidal anti‐inflammatory drugs (NSAID); high‐dose corticosteroids; and anti‐inflammatory agents such as infliximab, chemotherapy, and radiotherapy—all of which may be associated with significant toxicity—is uncertain .…”

Clinicopathological analysis of epithelioid inflammatory myofibroblastic sarcoma

“…Immunohistochemically, EIMS exhibited nuclear membrane or perinuclear accentuation staining pattern of ALK, which was observed in 100% (25/25) of cases from a selection of previous studies (Table III) (4,(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Another diagnostic immunophenotype is the diffuse strong expression of DES in almost all cases (92%; 23/25).…”

“…Clinically, EIMS occurs mainly in children and adolescents, although the overall range in age varies widely, with previous studies reporting on patients aged between 7 months and 65 years, with a median age of 33.4 years (Table II) (4,(12)(13)(14)(15)(16)(17)(18)(19)(20).…”

“…EIMS is mainly located in abdominal cavity (4). In Table II, 26 cases occurred in the abdominopelvic area (4,(12)(13)(14)(15)(16)(17)(18)(19)(20), with two cases located in the pleural cavity (21,22). The most common symptom of EIMS is abdominal pain prior to surgery (19).…”

“…Another diagnostic immunophenotype is the diffuse strong expression of DES in almost all cases (92%; 23/25). In addition, the tumors displayed variable expression of SMA (45.5%, 10/22), CD30 (57.9%, 11/19) and cytokeratin (20%, 4/20) (Table III) (4,(13)(14)(15)(16)(17)(18)(19)(20)(21)(22).…”