Background: Granular cell tumors (GCT) are rare Schwann cell-derived soft tissue tumors typically presenting as a solitary, painless nodule in adults in the 4th to 6th decades of life, rarely presenting in children. GCT most commonly originate from gastrointestinal mucosa of the tongue or oral cavity, and are 2-3 times more common in women. While generally benign, approximately 2% of cases may be malignant; therefore, GCTs are typically treated with local surgical control. Case: A 7-year-old male with sickle cell trait presented to clinic for a painless “pea-sized lump” on his penile shaft, which had been present since infancy but had recently grown larger. Ultrasound demonstrated a 1.8 cm lenticular-shaped mass on the dorsal mid shaft of the penis superficial to the fascial borders of the cavernous cavernosum. There was mild internal vascularity, but no invasion past fascial borders, surrounding soft tissue changes. On MRI, the mass was uniformly T1 iso-intense and T2 slightly hyperintense, with slight postcontrast enhancement. The mass was well-circumscribed, wrapped around the corpus cavernosum without invasion of the tunica albuginea, and exhibited uniform restricted diffusion, calcification, or internal fat. No lymph node involvement was noted on imaging. Surgical resection 8 months later noted a 3 cm mass, which now extended into the glans, with pathology consistent with benign GCT, with positive staining for S-100, CD68, SOX10, and calretinin, Ki-67 of 1%, and negative for SM actin. Due to depth of glans penetration, R2 resection was achieved based on the pediatric urologist’s decision to spare the glans, rather than performing a more aggressive distal penectomy. Post-operative MRI 4 months later demonstrated residual tumor with interval reduction in mass size. Additional investigation of the patient’s past medical history revealed that a benign GCT had been removed from the inside of his lip the previous year which helped support the final histopathologic diagnosis. While multifocal GCTs have been described in genetic syndromes, this patient had not undergone genetic testing to date. Read More

Meeting name: SPR 2025 Annual Meeting , 2025

Authors: Beckhorn Catherine, Lee Rachel, Cao Joseph

Keywords: MRI, Genitourinary, Soft-Tissue Tumors

Keratin-positive giant cell-rich tumor is a very rare subset of giant cell-rich tumors characterized by keratin-positive cells and HMGA2::NCOR2 gene fusion. First described in 2021, fewer than 40 cases have been reported in the English literature. Reported cases have shown a strong predilection for females in their 20s-30s and occur in both soft tissue and bone. The youngest reported case thus far has been a 13-year-old female. A 4-year-old previously healthy male presented to clinic with leg pain and a limp after falling on his right leg. Initial X-ray showed a lytic lesion on the right proximal tibia. Follow up MRI showed a 2 x 2.5 x 4.3 cm solid lesion in the proximal tibial metaphysis extending into the epiphysis. The mass was T1 and T2 hyperintense and demonstrated homogenous enhancement after contrast. No periostitis was noted on radiograph and no subperiosteal collection was present. No soft tissue component was identified. CT chest, abdomen, pelvis was ordered to rule out other sites of disease and showed multi-station lymphadenopathy throughout the right groin. Biopsy revealed tumor cells negative for H3G34W and H3K36M histone markers, specific for giant cell tumor of bone and chondroblastoma respectively. The cells were focally positive for AE1/AE3, a stain for keratin. Next-generation sequencing revealed an HMGA2::NCOR2 fusion confirming the diagnosis of keratin-positive giant cell-rich tumor. He underwent complete curettage of the lesion as well as excision of 2 inguinal lymph nodes that were negative for disease. Read More

Meeting name: SPR 2025 Annual Meeting , 2025

Authors: Lee Rachel, Beckhorn Catherine, Cao Joseph

Keywords: Bone Tumor, Musculoskeletal