Case studyCapillary hemangioblastoma of soft tissue: report of a case and review of the literature
Introduction
Capillary hemangioblastoma (CH) is an enigmatic tumor composed of lipidized “stromal” cells of uncertain etiology that are closely associated with an elaborate network of capillary-sized vessels. Sporadic examples of CH account for 50% [1] to 75% [2] of reported cases and arise as solitary lesions principally in the substance of the cerebellum. The remaining examples occur in the setting of von Hippel–Lindau (VHL) disease, where multiple tumors can be found in the cerebellum, medulla, pons, spinal cord, or retina. In addition, the origin of CH in parenchymal organs has also been documented in patients with VHL [3], [4], [5].
Examples of CH developing in sites outside the central nervous system and parenchymal organs are rare and subject to small series and case reports. The first report of CH arising in the soft tissues is credited to Brodkey et al [4], who, in 1995, chronicled a case of CH arising in the radial nerve of a 79-year-old woman. In the same year, Kline and Hudson [6] briefly described a CH occurring in the median nerve of 46-year-old woman. Later, Giannini et al [7] documented a case of CH arising in association with the sciatic nerve in a patient with VHL and two examples of CH developing in an intradural nerve root. Fanburg-Smith et al [3] delineated the first example of a soft tissue CH not attached to a peripheral nerve that developed in the retroperitoneum in a 47-year-old man. Recently, Michal et al [5] reported a CH arising in the soft tissue of the foot that did not involve a peripheral nerve and found no mutation of the VHL gene after comprehensive molecular analysis of tumoral tissue. Herein, we detail the clinicopathologic findings in the third reported case of a soft tissue CH unattached to peripheral nerve that was found in a patient with no known stigmata of VHL. We also review the English language literature pertaining to this rare occurrence and discuss the differential diagnosis of CH arising in soft tissue.
Section snippets
Case report
An otherwise healthy 53-year-old woman was referred to our hospital for clinical evaluation and surgical excision of a soft tissue lesion located in the left popliteal fossa. The patient presented with a 1-month history of swelling and tenderness in her left popliteal fossa. On palpation, the surgeon noted a mobile mass in the lateral head of the gastrocnemius muscle. T1- and T2-weighted magnetic resonance imaging showed a well-delineated, solid, enhancing mass within the skeletal muscle. The
Immunohistochemistry
Slides for immunohistochemical staining were prepared from formalin-fixed, paraffin-embedded tissue. The slides were immersed in a citrate buffer at pH 6.0, pretreated in a microwave pressure cooker for 20 minutes at 92°C to 95°C, and then stained on either a Ventana Benchmark or a Ventana ES immunostainer (Ventana Medical Systems, Tucson, Ariz) using one of the following primary antibodies: S-100 protein (50 μg/mL, Ventana), CD31 (1:40, clone JC/70A, DakoCytomation, Carpinteria, Calif), CD34
Gross findings
Examination of the resection specimen revealed a well-circumscribed, nonencapsulated, 2-cm lobulated mass with a firm consistency and a spongy, dull yellow cut surface. Necrosis and hemorrhage were not present. The mass was completely surrounded by a thin fibrous pseudocapsule and skeletal muscle. The lesion was not associated with any visible nerves (Fig. 1A).
Microscopic findings
At low-power magnification, the tumor appeared as a well-circumscribed nodule with a lobulated contour and was enveloped by a fibrous
Discussion
We report the sixth case of a CH arising in the somatic soft tissues and only the third such lesion not associated with a peripheral nerve (Table 1). Our patient, a 53-year-old African American woman, had no known family history or clinical stigmata of VHL disease.
We observed some interesting clinical differences between the 6 examples of soft tissue CH and CH developing within the central nervous system (central CH), although the number of cases of the former lesion is admittedly small in
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