The clinical course began with what appeared to be a subungual hematoma, a collection of blood beneath the toenail of the kind familiar to anyone who has ever dropped a heavy object on a foot. Trephination, a procedure in which a small hole is made in the nail plate to relieve pressure and drain the trapped blood, was performed under the assumption that this was the problem. But two weeks after the procedure, the swelling had not resolved and the dark discoloration beneath the nail persisted. A clinical photograph taken at that point documented marked soft-tissue swelling of the toe along with the stubborn subungual discoloration, findings that prompted the team to look deeper. What the imaging revealed would rewrite the entire diagnostic picture.

A frontal radiograph of the toe demonstrated a destructive, predominantly lytic process replacing the entire distal phalanx, the small bone at the very tip of the great toe, in the region distal to the open physis, the growth plate that in children remains a cartilaginous zone between the bony shaft and the epiphysis. The normal trabecular architecture, the delicate internal lattice of bony struts that gives healthy bone its strength and appearance on X-ray, had been completely lost. In its place the radiologists described a pattern of bone destruction that was permeative to moth-eaten, terms that refer to the way aggressive lesions riddle bone with countless tiny, ill-defined holes rather than producing one clean cavity. Cortical thinning and disruption were also present, meaning the dense outer shell of the bone had been eroded and breached by the growing tumor.

Notably, the physeal contour remained intact. The growth plate, a structure that in growing children acts as a boundary between bone segments, had not yet been visibly breached by the process, even though the bone beyond it had been substantially destroyed. This detail matters because the behavior of tumors relative to the physis can offer clues about their nature and extent, and because preserving the physis has implications for surgical planning in a skeletally immature patient. Even with this anatomical nuance, the overall radiographic appearance was unmistakably aggressive. In pediatric bone radiology, permeative destruction with cortical breakdown is a red flag that demands consideration of malignancy, whatever the clinical history might suggest.

Given the boy’s history of repeated crush injuries, chronic osteomyelitis, a persistent infection of the bone, was the initial suspicion. This was a reasonable hypothesis. Chronic osteomyelitis can follow trauma, can produce lytic bone destruction, and is far more common than a malignant tumor in the distal phalanx of a toe. The distinction, however, could not be made on imaging alone, and biopsy was performed. The tissue diagnosis established Ewing sarcoma, a small round blue cell tumor driven in the vast majority of cases by a characteristic chromosomal translocation that fuses the EWSR1 gene with members of the ETS family of transcription factors, most commonly FLI1. This fusion protein acts as an aberrant transcriptional regulator, driving the uncontrolled proliferation that defines the disease. Definitive diagnosis of Ewing sarcoma typically rests on a combination of histology, immunohistochemistry demonstrating membrane staining for CD99, and molecular confirmation of the pathognomonic fusion.

The rarity of this presentation cannot be overstated. Ewing sarcoma is the second most common primary malignant bone tumor in children and adolescents, yet it has a strong predilection for specific locations: the pelvis, the femur, the tibia, the ribs, and the bones of the chest wall. It typically arises in the diaphysis or metaphysis of long bones, and involvement of the small bones of the hands and feet is exceptionally uncommon. Within those small bones, the distal phalanges are the rarest of sites. The authors of the report note that Ewing sarcoma of the toes is exceptionally rare, with distal phalangeal involvement reported in only a handful of cases worldwide. Every published instance therefore becomes a teaching case, because the accumulated experience of most radiologists and oncologists with tumors at this site is close to zero.

That rarity carries a real clinical cost, and it is the central message of the report: unusual location and clinical resemblance to trauma or infection may delay recognition. In this case, three months elapsed between the onset of symptoms and the establishment of the correct diagnosis, with the interval punctuated by procedures and treatments aimed at conditions the toe did not actually have. Delay in diagnosing Ewing sarcoma is not a trivial matter. The tumor is highly aggressive, with a capacity for local infiltration and early hematogenous metastasis, most commonly to the lungs and to other bones. Modern multimodal therapy, combining intensive multi-agent chemotherapy with local control through surgery, radiation, or both, has transformed five-year survival for localized disease, but outcomes deteriorate sharply once metastatic spread has occurred. Every week of diagnostic delay is a week in which a curable localized tumor has the opportunity to become something far worse.

The case also illustrates a broader principle in radiology and clinical medicine: the history is a guide, not a verdict. A plausible mechanism of injury, a swollen painful digit, and a dark nail can lull clinicians into anchoring on subungual hematoma and its complications, and later on osteomyelitis, without ever questioning whether the underlying process might be neoplastic. The authors urge radiologists to maintain suspicion for malignancy when confronted with aggressive phalangeal bone destruction, even when the clinical history suggests a more common process. In practical terms, this means that when an X-ray of a small bone shows permeative destruction, cortical disruption, and loss of trabecular architecture, the radiology report should explicitly flag the possibility of an aggressive neoplasm and recommend further evaluation, including magnetic resonance imaging to define the soft-tissue extent and marrow involvement, and ultimately biopsy to obtain tissue.

For the wider audience beyond the radiology reading room, the story is a reminder that persistent symptoms that fail to respond to appropriate treatment deserve escalation, not repetition. A crushed toe that keeps hurting and swelling for months, that darkens beneath the nail and does not improve after drainage, is not behaving like a simple injury. Children and adolescents are not immune to malignant bone tumors, and while the odds overwhelmingly favor benign explanations for a sore toe, the consequences of missing the rare alternative are profound. The authors of this report, who obtained informed consent from the patient’s parent for publication of the clinical information and images, have contributed a documented example of exactly this diagnostic trap, complete with the clinical photograph and radiograph that show how deceptive the presentation can be.

Ultimately, the case of the great toe distal phalanx joins a small but important body of literature documenting Ewing sarcoma in the most peripheral bones of the body. It underscores the value of open-access publication in pediatric radiology, allowing a single instructive case to reach clinicians everywhere who might otherwise never encounter this entity in their own practices. It reinforces the technical vocabulary of aggressive bone lesions, permeative and moth-eaten patterns, cortical disruption, and physeal relationships, as more than academic descriptors: they are the visual signatures that separate a tumor from an infection and from a healed crush injury. And above all, it demonstrates that in medicine, as in the imaging itself, what lies beneath the surface can only be known when someone thinks to look, and keeps looking when the first answer does not fit.

Subject of Research: Ewing sarcoma of the great toe distal phalanx in a pediatric patient

Article Title: Ewing sarcoma of the great toe distal phalanx

Article References: Ewing sarcoma of the great toe distal phalanx. (n.d.). https://doi.org/10.1007/s00247-026-06773-1

Image Credits: AI Generated

DOI: 10.1007/s00247-026-06773-1

Keywords: Ewing sarcoma, pediatric radiology, bone tumor, distal phalanx, great toe, lytic bone lesion, osteomyelitis, subungual hematoma, biopsy, radiography, sarcoma, diagnostic delay