|Home | About | Journals | Submit | Contact Us | Français|
Inflammatory myofibroblastic tumor (IMT) is a neoplasm of intermediate biologic potential. Only a few cases of IMT in the spermatic cord have been reported. It was earlier included in a wide spectrum of reactive and neoplastic lesions called “inflammatory pseudotumors”. It commonly presents as a painless scrotal mass, usually in children and young adults.
We present a case of IMT in the spermatic cord who based on clinical, radiological and cytological findings underwent surgical exploration of left scrotal sac. The mass was separate from the left testis and left epididymis, and was closely adherent to pampiniform plexus of veins. Wide excision of the mass was done. Histology and immunohistochemistry suggested IMT.
IMT is a myofibroblastic spindle cell proliferation with chronic inflammatory infiltrate. Surgical exploration is essential as clinically and radiologically benign or malignant nature of mass cannot be distinguished. The diagnosis of IMT is based on the histological features and is substantiated by immunomarkers.
In clinically distinct masses, based on frozen section, either tumor excision or radical orchidectomy can be performed. The prognosis is excellent after complete surgical excision of spermatic cord IMT. Careful long-term follow-up is essential, because of the possibility of recurrence, though rare in this site.
Inflammatory myofibroblastic tumor (IMT) is a neoplasm of intermediate biologic potential.1 IMT was formerly included in a wide spectrum of reactive and neoplastic lesions known as “inflammatory pseudotumors”. They have also been described in the literature under names such as atypical myofibroblastic tumor, pseudosarcomatous myofibroblastic proliferation, pseudosarcoma, plasma cell granuloma, and proliferative funiculitis. Over the last two decades, IMT came to be known as a distinct tumor with its typical clinical, pathological and molecular features. Inflammatory pseudotumor was first described in the lung where it was hypothesized to be a reparative postinflammatory process.2,3 Its exact etiology still remains unknown. Subsequently similar lesions were reported from extrapulmonary sites also. Accurate data regarding the incidence, prevalence and anatomical distribution of IMT are difficult to obtain due to the use of the terms “inflammatory pseudotumor” and “IMT” interchangeably in the literature. The abdominopelvic region, lung, mediastinum, and retroperitoneum are frequent sites. Only a few cases of IMT in the spermatic cord have been reported.4–6 We present the case of a young man with an IMT involving the spermatic cord, closely adherent to the pampiniform plexus of veins.
A 22-year-old male presented with a painless left scrotal mass of 7 months duration. There was no history of trauma, fever, recurrent urinary tract or sexually transmitted infections and no past history of exposure to tuberculosis. Physical examination revealing a nontender, firm oval-shaped, 3 cm × 3 cm sized mass with nodular surface was palpable over the superior pole of left testis. It could be separated from left testis. Skin over the mass was normal. The mass was mobile in the inguinal canal but it was restricted in the subcutaneous plane, suggestive of adherence to the cord structures. Hydrocele excluded. There was no inguinal lymphadenopathy. The external genitalia including both testes were normal. Abdominal examination was normal.
Sonography of scrotum showed a solid, heterogeneous mass of size 3 cm × 3 cm with internal vascularity in the left scrotal sac, separate from left testis and left epididymis. The testes and epididymis were normal sized and there was no free fluid in right or left scrotal sac. Abdominal sonography was normal. Fine needle aspiration cytology of the mass revealed clusters of oval to spindle shaped cells in a proteinaceous background.
Left scrotal exploration demonstrated the tumor, closely adherent to pampiniform plexus of veins. Intra-operative Doppler examination was done to identify the testicular artery. Testicular artery and vas deferens were isolated. Wide excision of the mass with surrounding cremaster muscle and a leash of veins which seemed to enter the mass were excised.
Macroscopically, the mass was globular, gray–brown, measuring 4.5 cm × 3.5 cm × 2 cm with capsulated external surface (Fig. 1). Its cut surface was gray–white, firm to hard, partially embedded. Microscopic examination revealed inflammatory cells, predominantly plasma cells and lymphocytes admixed with myofibroblasts and fibroblasts in a stroma of abundant hyalinised collagen (Fig. 2). Focal dystrophic calcification was seen. There was no evidence of necrosis or atypia. Immunohistochemically, the tumor was strongly positive for vimentin (Fig. 3), and focally positive for CD34. Epithelial membrane antigen was positive in the plasma cells. Staining for anaplastic lymphoma kinase (ALK) (Fig. 4), smooth muscle actin (Fig. 5), desmin, S100 and cytokeratin were negative. The findings were consistent with an IMT arising from the spermatic cord. Serum IgG4 level was 1.49 g/L which is normal (reference: 0.03–2 g/L), thus excluding IgG4-related sclerosing disease.
IMT is characteristically composed of spindle myoepithelial cell proliferation accompanied by inflammatory infiltrate of plasma cells, lymphocytes and eosinophils. It usually occurs in the soft tissues and viscera of children and young adults. However, proliferative funiculitis (this term was earlier used to denote an IMT involving the spermatic cord) preferentially affects men of middle to advanced age.4–6 IMT may span the entire age range. The clinical presentation depends on the site of origin. In spermatic cord IMT, the presentation is usually a painless scrotal mass of variable duration.
Ultrasonography (US) is the initial imaging modality of choice in a case of scrotal mass that helps to distinguish intratesticular from extratesticular lesion and solid from cystic lesion. Intratesticular lesion has a high likelihood of malignancy, whereas extratesticular lesion is usually benign. Benign conditions such as spermatocele, varicocele, or tuberculosis must be ruled out. MR imaging helps if US is not conclusive. CT can distinguish a spermatic cord tumor from a retroperitoneal process extending in to the scrotum.7
Macroscopically, IMTs can be firm or fleshy with a white or tan cut surface. Calcification, hemorrhage and necrosis are rare. Histologically, IMTs have three basic patterns: a myxoid/vascular pattern, a compact spindle cell pattern and a hypocellular fibrous pattern, which are often seen in combination within the same tumor.8 The myxoid/vascular pattern has a fasciitis-like appearance, with loosely arranged plump spindle cells in a myxoid stroma and a prominent vasculature and its inflammatory infiltrate often contains more neutrophils and eosinophils and fewer plasma cells than in the other two patterns. The compact spindle cell pattern is characterized by a proliferation of spindle cells with a fascicular architecture admixed with numerous plasma cells and lymphocytes in a collagenous stroma, in line with our case. The fibromatosis-like pattern is relatively hypocellular, with elongated spindle cells in a densely collagenous background containing scattered lymphocytes, plasma cells and eosinophils. The spindle cells of IMT are typically uniform and predominantly myofibroblastic in appearance with oval to spindle-shaped vesicular nuclei, small sized nucleoli, and eosinophilic to amphophilic cytoplasm. Atypical mitoses are rare. Fine needle aspiration cytology showing such features may not be conclusive of IMT; excision biopsy is more reliable.
Immunohistochemistry helps to exclude similar tumors like myxofibrosarcoma, inflammatory fibrosarcoma and malignant fibrous histiocytoma from the differential diagnosis. IMTs are usually immunoreactive for vimentin, muscle-specific actin, smooth muscle actin, desmin, anaplastic lymphoma kinase (ALK) and sometimes for cytokeratin or epithelial membrane antigen.1,4 ALK reactivity could be a favorable prognostic indicator in IMT as distant metastasis was not found among ALK-positive lesions.9 According to a recent study, IMT has a similar morphological appearance as that of IgG4-related sclerosing disease, especially in areas with prominent myofibroblastic proliferation mixed with inflammatory cells. ALK expression, which is found commonly in IMT, helps to differentiate it from IgG4-related sclerosing disease.10
IMTs are classified as tumors of intermediate biologic potential by the World Health Organization, due to a tendency for local recurrence and a small risk of distant metastasis.1 The recurrence rate varies by anatomical site, it is 25% for extrapulmonary IMTs.8 The prognosis after complete surgical excision of paratesticular IMT is excellent.11 These cases should be followed up because some tumors may recur when resection is incomplete. Recurrence is more common in multiple intra-abdominal tumors and those in sites where complete surgical resection is difficult. Tumor recurrence is very infrequent after complete surgical resection of a solitary lesion.12 Radical orchidectomy was performed in most of the paratesticular IMTs for suspicion of malignancy. Chakrabarti and Shetty reported radical orchidectomy for a spermatic cord IMT presenting as a stony hard right scrotal mass.13 Yee et al. reported a case of undescended left testis with IMT from left spermatic cord presenting as a left lower abdominal mass which was excised en bloc with left testis.14 Frozen section helps to exclude malignancy prior to performing radical surgery.
IMT though rare should be considered in the differential diagnosis of a paratesticular mass. Clinically and radiologically it is difficult to distinguish the origin of the mass and to differentiate its benign or malignant nature, thus surgical exploration is essential. Either a complete tumor excision or radical orchidectomy could be performed, based on frozen section of a clinically distinct mass. Immunohistochemical study helps to distinguish IMT from other histologically similar tumors. Long-term follow-up is suggested although recurrence is very infrequent following complete excision of a solitary lesion of IMT.
The authors declare that they have no conflict of interest.
Noora Rafeek was involved in conception and design, acquisition of data, data analysis, and interpretation, manuscript writing and final approval.
Leena Dennis Joseph was involved in acquisition of pathological data, data analysis, and interpretation, manuscript writing and final approval.
Swaminathan Rajendiran was involved in acquisition of pathological data, data analysis, and interpretation and final approval.
Cunnigaiper Dhanasekaran Narayanan was involved in conception and design, acquisition of data, data analysis, and interpretation, manuscript writing and final approval.