[1087] Testicular Fibrothecoma: A Report of 16 Cases

Miao Zhang, Chia-Sui Kao, Thomas M Ulbright, Jonathan I Epstein. Johns Hopkins Hospital, Baltimore, MD; Indiana Univerity School of Medicine, Indianapolis, IN

Background: Fibrothecomas of the testis are rare with only a single prior series of 3 cases.
Design: A search of pathology reports from two institutions between 1997 and 2012 identified 16 patients with testicular fibrothecomas.
Results: 15/16 patients had orchiectomy, 1 an excisional biopsy. The mean age was 44 years (16 to 69). Of the 15 patients with information, 14 presented with a palpable testicular mass and 1 with scrotal heaviness. Prior histories included bilateral orchidopexy as a child (n=1) and testicular atrophy receiving testosterone replacement (n=1). The average size was 1.8 cm (0.5 to 7.6 cm). Of 8 cases with a gross description,6 were white-tan (n=6) or red-tan (n=1) well-circumsribed masses, and 1 was an ill-defined yellow-tan lesion with hermorrhage. All cases were intratesticular although 13/16 were attached to the tunica albuginia with others centered around the rete testis (n=2), or indeterminate on biopsy (n=1). 11/16 were fairly well circumscribed although not encapsulated with 1 infiltrative and 4 unevaluable. 4/16 showed entrapment of seminiferous tubules. 50% showed mixed storiform and short fascicular patterns, 6 storiform only, and 2 short fascicles only. 50% of lesions were hypercellular. 9/16 exhibited small dilated blood vessels. Cases were equally split between plumper ovoid and spindled pointed nucle, both lacking prominent nucleoli. 11 had 0-2 mitoses/10 HPF, 3 had 4-5/10HPF, and 2 had 9-10/10HPF. Collagen deposition ranged from none to extensive with most moderate (5/16) either in bands or investing single cells. IHC positivity was as follows: inhibin (11/12, patchy to diffuse); calretinin (4/9); Melan-A (4/4); pan keratin (4/10); BCL2 (3/4); CD34 (3/7); S-100 (4/8); muscle specific actin (6/6); and desmin (5/6). Patients were followed for a mean of 29 months (6-108 mos.). All were well with no evidence of disease. Of the 2 men with 9-10 mitoses/10 HPF, 1 died of other causes 6 years later and the other had no evidence of disease at 5 years.
Conclusions: Testicular fibrothecomas are rare benign neoplasms with somewhat variable histology that may show worrisome features including minimal invasion into surrounding testis, high cellularity, and elevated mitotic rates. Some may resemble monophasic synovial sarcoma, a neoplasm not reported in the testis, but show collagen deposition around individual cells, frequent inhibin and occasional CD34 staining, and lack a hermangiopericytomatous vasculature. Their immunoprofile is variable and typically not diagnostic.
Category: Genitourinary (including renal tumors)

Tuesday, March 5, 2013 9:00 AM

Proffered Papers: Section A, Tuesday Morning


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