Hyalinized stroma separately ill-defined 'lobules' of cellularity. The connective tissue separating the pseudolobules can range from densely hyalinized to hypocellular and edematous.
The cellular component consists of spindle cells and round cells with eosinophilic vacuolated cytoplasm. The latter represents degenerated lutein cells.
Yet another area demonstrates an extensively hyalinized background separating loosely aggregated cellular areas.
Another case shows the two main cell populations comprising the cellular areas: plump spindle cells and rounded cells containing pink vacuolated cytoplasm.
Hemangiopericytoma-like or staghorn-shaped vessels (ramifying, branching thin-walled vessels) are a prominent feature in this area.
A different case exhibits a more edematous stroma which is otherwise sclerotic.
Sclerosing stromal tumor is a rare benign ovarian stromal tumor that occurs in teenagers and women in their 20s. The tumor is invariably unilateral and ranges from 1.5 to 20 cm. The mass is well-defined and in some instances, can be shelled out during surgery. The cut surface is either solid or solid with a cystic component. Occasionally, the tumor will have a single central cyst.
Microscopically, the tumor has a pseudolobular appearance at low power, with cellular nodules separated by bands of edematous, hypocellular or collagenized connective tissue. The cellular areas are composed of an admixture of spindle cells, myoid cells, polygonal theca-like cells with abundant vacuolated eosinophilic cytoplasm (also described as round lutein cells or degenerated lutein cells). A network of thin-walled branching vessels (hemangiopericytoma-like) can be seen.
80% of patients are younger than age 30 (younger than those with fibromas or thecomas). Typically presents with menstrual irregularities or a pelvic mass. Rarely, the tumor may produce hormones leading to androgenic or estrogenic manifestations. Ascites, Meigs syndrome and/or elevated CA-125 are uncommon, but have been reported.1,2
Since the tumors are benign and occur in young women, excision or unilateral salpingo-oophrectomy is the treatment of choice.
1 Nucci MR, Oliva Esther. Gynecologic Pathology: Foundations in Diagnostic Pathology. Philadelphia, PA: Elsevier: 2009: 457-460.
2 Fletcher CDM, ed. Diagnostic Histopathology of Tumors. 3rd Ed. Philadelphia, PA: Elsevier; 2007: 602.
3 Mills SE, ed. Sternberg's Diagnostic Surgical Pathology.4th Ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2004: 2586-7.