Inwards, Carrie Y.

BACKGROUND Ecchordosis physaliphora (EP), a benign extraosseous notochordal remnant, has been found in 0.4%–2% of autopsies. It most commonly occurs on the dorsal surface of the clivus and is rarely symptomatic. Extraosseous notochordal lesions involving the spine are also rare, with the majority being diagnosed as chordoma. OBSERVATIONS The authors report a case of an extradural extraosseous notochordal lesion within the left L5–S1 nerve root foramen resulting in left lumbar L5 radiculopathy in a 46-year-old woman. Microdecompression at the left lumbar L5–S1 level permitted successful removal of the lesion and complete resolution of radiculopathy. The combined histopathological and retrospective imaging findings were felt to be consistent with EP. Thirty-nine-month follow-up imaging revealed no recurrence of the lesion, and the patient remains asymptomatic at last follow-up. LESSONS Challenges in diagnosing EP, particularly distinguishing it from extraosseous chordoma, and the implications of diagnostic terminology on the management of these lesions are discussed. https://thejns.org/doi/10.3171/CASE26203

Case: A 53-year-old man sustained an injury to his left index finger and underwent presumably traumatic neuroma excision from the radial digital nerve 2 years ago. He presented with a painful mass distal to the prior site of neuroma excision with distinctly different symptoms from those that led to his index surgery. Thus, he underwent excisional biopsy of the mass which was adherent to his radial digital nerve consistent with a benign glomus tumor on histologic examination. Conclusion: Digital nerve glomus tumors are rare. In most of the cases, some portion of the digital nerve requires excision but decreased pain can be expected.

Aims . Fibrous dysplasia (FD) is a benign fibro-osseous neoplasm that most commonly arises in the ribs, femur, and craniofacial bones. We analyzed features of FD arising in the spine/short tubular/small bones of the hands/feet (STSBHF), specifically assessing for pattern of bone formation (conventional, complex/anastomosing, psammomatoid/cementum like), myxoid change, and presence of osteoclast-type giant cells. Materials and methods . A total of 1958 cases of FD were reviewed, of which 131 arose in the spine/STSBHF representing 2.5% of institutional and 10% of consultation cases, respectively. Eighty-six cases had material available for review. Anatomic sites included vertebrae ( n = 58, 67%), short tubular bones ( n = 20, 23%), and small bones of the hands/feet ( n = 8, 9%). The most common morphologic pattern of bone identified was conventional ( n = 77, 90%), followed by complex/anastomosing ( n = 22, 26%) and psammomatoid/cementum like ( n = 22, 26%). Eighteen cases (21%) had matrix-poor areas. Hypercellular areas were identified in 6 cases, 2 cases of which showed matrix-poor areas. Osteoclast-type giant cells were noted in 9 cases and myxoid change was present in 3 cases. Radiologic imaging studies available for 41 cases nearly all demonstrated features typical of FD, but the diagnosis was not predicted due to the unexpected location. Conclusions . FD arising in the spine/STSBHF is rare and frequently results in expert consultation. A significant number of cases exhibited less commonly recognized patterns of bone formation, and stromal changes including osteoclast-type giant cells, and matrix poor areas. Furthermore, imaging features in the STSBHF are often less specific. Awareness of the morphologic spectrum at these locations coupled with radiologic correlation should aid in accurate classification.

Abstract Context. —Sarcomatous transformation is a rare complication of Paget disease of bone. Prognosis in patients with other types of sarcomas arising in bone has improved in the last several decades because of therapeutic advances. However, because of the rarity of Paget sarcoma, outcome studies in these patients are limited. Objective. —To determine whether prognosis for Paget sarcoma has improved. Design. —Seventy cases of sarcomas arising in the setting of Paget disease were collected, and the histologic and clinical findings were reviewed. Clinical follow-up was obtained in 67 cases. Results. —Sarcoma arising in Paget disease tended to arise in older men (46 men, 24 women; age range, 31–88 years; mean age, 66 years) and predominated in the axial skeleton (n = 37), especially in the pelvis. Thirty-three patients had a clinical history of Paget disease ranging in duration from 16 months to 30 years (mean, 15 years). No significant difference in incidence between monostotic (n = 33) and polyostotic (n = 36) disease was noted. Most tumors were osteosarcomas (88%). All tumors were high grade. Follow-up information was obtained in 67 of 70 cases (range of follow-up, 1–252 months). Survival ranged from 1 month to 20 years, with a 5-year survival rate of 10%. Conclusions. —Prognosis remains poor in patients with Paget sarcoma. There is no significant correlation between the number of bones involved with Paget disease or the duration of disease and development of Paget sarcoma. Poor prognosis in Paget sarcoma is unrelated to site or stage at presentation.

Giant cell tumor of bone (GCT) is a benign locally aggressive neoplasm composed of mononuclear cells admixed with innumerable osteoclast-type giant cells. H3F3A gene mutations producing mutant histone protein product H3.3 have been identified in 96% of GCT; mutant H3.3 is reliably demonstrated by immunohistochemistry. GCT may contain woven bone and rarely, neoplastic cartilage nodules which causes diagnostic challenges with aggressive neoplasms such as osteosarcoma. We describe the features of GCT with cartilage matrix and report the next-generation sequencing findings in a subset of tumors. Seventeen cases of GCT with cartilage matrix form the cohort: 7 males and 10 females, 13 to 55 (mean: 25) years old. Tumors involved the fibula (6), femur (6), and patella, tibia, humerus, S1, and scapula (1 case each). Tumors were radiolucent, circumscribed, lytic, and expansile. All contained classic GCT, foci of cartilage matrix, and trabeculae of woven bone. Immunohistochemistry showed diffuse staining for H3.3 in 9/9 cases and 1 case was positive for S100 and SOX9 in the cartilage areas. Next-generation sequencing showed a mutation in the H3F3A gene in 6/6 cases. On follow-up, 2 patients who underwent resection showed no disease after 12, and 7 months, respectively. Three patients had recurrences 10, 12, and 27 months after curettage; there were no metastases. GCT with cartilage matrix is uncommon. The cartilage matrix is associated with woven bone suggesting the neoplastic cells may differentiate into chondrocyte-like and osteoblast-like cells. Recognition of this neoplasm is important to prevent misdiagnosis and overtreatment of affected patients.

Benign notochordal cell tumors (BNCTs) are considered to be benign intraosseous lesions of notochord origin; however, recent spine studies have suggested the possibility that some chordomas arise from BNCTs. Here, the authors describe two cases demonstrating histological features of BNCT and concomitant chordoma involving the clivus, which, to the best of the authors’ knowledge, have not been previously documented at this anatomical site.An 18-year-old female presented with an incidentally discovered clival mass. Magnetic resonance imaging revealed a 2.8-cm nonenhancing lesion in the upper clivus that was T2 hyperintense and T1 hypointense. She underwent an uneventful endoscopic transsphenoidal resection. Histologically, the tumor demonstrated areas of classic chordoma and a distinct intraosseous BNCT component. The patient completed adjuvant radiation therapy. Follow-up showed no recurrence at 18 months.A 39-year-old male presented with an incidentally discovered 2.8-cm clival lesion. The nonenhancing mass was T2 hyperintense and T1 hypointense. Surgical removal of the lesion was performed through an endoscopic transsphenoidal approach. Histological analysis revealed areas of BNCT with typical features of chordoma. Follow-up did not demonstrate recurrence at 4 years.These cases document histologically concomitant BNCT and chordoma involving the clivus, suggesting that the BNCT component may be a precursor of chordoma.

AimsChondroblastomas (CB) are rare bone tumours that typically arise in the epiphysis/apophysis of long bones in skeletally immature patients. We explore the clinicopathological features of CB presenting in adults.Methods and resultsCB in patients ≥20 years of age were retrieved from our institutional archives. Thirty‐nine CB were identified (29 male/10 female; aged 20–54 years). Twenty (51%) cases occurred in long tubular bones, 10 (26%) in small bones of the feet, five (13%) in flat bones and four (10%) in the patella. All cases showed classic cytological features of CB, and chondroid matrix was universally present. Calcification was identified in 10 cases (26%), including various combinations of serpiginous (n = 7), punctate (n = 6), classic chicken‐wire (n = 4) and psammomatous (n = 2) patterns. Haemosiderin (n = 19), woven bone (n = 13), secondary aneurysmal bone cyst formation (n = 8), foamy macrophages (n = 4), hyalinised vascular spaces (n = 2) and cholesterol clefts (n = 2) were noted. Follow‐up information (n = 32, 1–452 months) revealed local recurrence in three patients, all >40 years of age with flat bone origin, one of which developed pulmonary metastases 132 months after initial diagnosis.ConclusionsCB in patients >20 years of age more frequently involves the short bones of the hands/feet and flat bones compared to those arising in their younger counterparts. A subset may harbour extensive serpiginous or psammomatous calcification rather than the classic chicken‐wire pattern. Although the overall local recurrence rate in adulthood is approximately 10%, all three patients with recurrent disease had tumours involving flat bones, suggesting that tumours arising in these sites may behave more aggressively.