An unusual cranial manifestation of B-cell precursor lymphoblastic lymphoma in 10-year-old girl

Abstract

Pediatric B-cell precursor lymphoblastic lymphoma (BCP-LBL) is a rare subtype of non-Hodgkin lymphoma with a predominantly extramedullary presentation. Cutaneous and subcutaneous involvement, particularly in the head region, is a recognized manifestation; however, presentation as a solitary scalp mass mimicking a benign surgical lesion remains diagnostically challenging. A 10-year-old female patient presented to the Neurosurgery Department for a growing mass in the right frontal region of the scalp for the past 4 months. After excision, the mass was diagnosed as BCP-LBL and the patient was referred to oncologic treatment. This report aims to increase awareness among surgeons and physicians that persistent or progressive pediatric scalp lesions, even when clinically benign-appearing, may represent an underlying malignant hematologic disease requiring prompt histopathological verification and specialist referral.

Case presentation

A 10-year-old female patient presented to Pediatric Neurosurgery Department for a growing solitary 4 × 3 cm scalp mass in the right frontal region for the past 4 months. The mass was firm, poorly mobile under the skin and non-painful. The skin over the lesion was reddish brown and dry. On physical examination, the patient was neurologically intact, the lymph nodes were not enlarged, and there were no other skin changes. The parents denied head trauma and oncologic disease in family history. The girl did not take medications on a regular basis. On primary examination, a local physician suspected an organized subcutaneous clot and advised the parents to wait until it resolves but they were concerned enough to consult a pediatric neurosurgeon.

A CT and MR scans revealed an isolated lesion limited to subcutaneous tissue, with no periosteum or bone invasion (Fig. 1). Given the history of a constant rapid growth of the mass, the neurosurgeon decided for surgical excision. Intraoperative appearance suggested a cutaneous lesion respecting the periosteum (Fig. 2). Pathology revealed lymphoblastic infiltration of the scalp consistent with precursor B cell differentiation. Immunohistochemical examination showed the expression of TdT, CD10, Pax5, and no expression of S100, PRAME, SOX10, p16, Melan-A, and synaptophysin (Fig. 3). The Ki-67 index was nearly 100%. These findings were considered typical for pre-B-lymphoblastic leukaemia/lymphoma. The diagnosis prompted supplementary hematologic and oncologic work-up but the lesion had regrown within 1 month from the surgery. The [¹⁸F] FDG PET/CT scan revealed increased tracer uptake in the subcutaneous tissue of the right frontal and temporal regions, as well as in the left mastoid region (Fig. 4).

Fig. 1.

Pre-operative CT scan, sagittal plane, demonstrating a subcutaneous mass (white arrow) in the frontal region

Fig. 2.

Intra-operative photographs, surgeon’s perspective. a Elevation of skin exposing the subcutaneous mass (LBL) respecting the periosteum (P). b Separation of the mass (LBL) from the subcutaneous tissue (SC). c Macroscopic appearance of the mass (LBL) after dissection

Fig. 3.

Histopathological slides from the excised lesion: a H&E, × 200 – dense monomorphic lymphoid infiltration; b H&E, × 400 – high mitotic activity and starry-sky pattern; c TdT (immunostain) – strong nuclear positivity in tumor cells; d PAX5 (immunostain) – diffuse nuclear positivity confirming B-cell lineage

Fig. 4.

Axial 18F-FDG PET/CT scan showing an increased tracer uptake in the subcutaneous tissue of the right frontal region (a), right temporal region (b), and left mastoid region (c)

Based on the clinical picture and the result of the pathology, the diagnosis of pediatric B-cell precursor lymphoblastic lymphoma (BCP-LBL) stage II was established. Treatment according to EURO-LB 2002 was initiated. After an induction phase a complete metabolic and morphological remission was achieved. In 1 year, follow-up the girl remains in complete remission during maintenance therapy.

Discussion

B- and T-cell non-Hodgkin lymphomas account for approximately 4–6% of malignant neoplasms in children [1]. Pediatric lymphoblastic lymphomas (LBLs) are predominantly of T-cell origin, whereas B-cell lymphoblastic lymphomas (B-LBLs) represent only 10–20% of cases [2–4]. Although LBL is an important subtype of pediatric non-Hodgkin lymphoma, B-LBL remains uncommon, accounting for only approximately 1% of all pediatric hematologic malignancies [2,5]. It is observed primarily in adolescents and young adults and less frequently in very young children, with a slight male predominance [5].

Contemporary diagnostic guidelines emphasize that lymphoblastic leukemia/lymphoma represents a biologically heterogeneous group of precursor lymphoid neoplasms, for which accurate classification requires integration of morphological, immunophenotypic and, when available, genetic features [6]. BCP-LBL should be regarded as a predominantly extramedullary malignancy. Lin et al. reported that precursor B-cell lymphoblastic lymphoma most commonly involved extranodal sites, particularly the skin, bone and soft tissue, with a low propensity for leukemic involvement [7]. Similarly, in a large pediatric BCP-LBL cohort, Kroeze et al. reported lymph node involvement in 62% of patients, followed by bone lesions in 34% and skin/subcutaneous lesions in 30% [8]. Many lesions were located in the head and neck region, including facial skin lesions or subcutaneous masses [8]. Therefore, the rarity of the present case does not lie in cutaneous or head and neck involvement itself, but rather in its presentation as a solitary, slowly enlarging frontal scalp mass mimicking a benign neurosurgical lesion.

Recent literature describes various head and neck presentations of B-LBL, including lesions of the nasal cavity and paranasal sinuses, facial region, temporal region, scalp, infraorbital region and postauricular region [9–16]. This unusual clinical presentation carries a risk of underdiagnosis and misinterpretation as a harmless lump, whereas the aggressive nature of B-LBL requires prompt referral for hematologic evaluation and treatment. B-LBL may also mimic infectious or inflammatory conditions, such as Pott’s disease, which can result in unnecessary antibiotic therapy and delay the oncologic diagnosis [17]. Timely diagnosis is crucial, as untreated lymphoblastic lymphoma can progress rapidly. Systemic chemotherapy remains the main curative treatment. Surgical excision alone is not sufficient, as relapse may occur rapidly. Nevertheless, despite its aggressive biology, pediatric B-LBL is a potentially curable disease, with reported survival rates of approximately 75–90% [3,18].

Recent clinical trials have explored targeted and immunotherapeutic approaches in pediatric patients with refractory or relapsed B-LBL or lymphoblastic leukemia. Inotuzumab ozogamicin, an anti-CD22 antibody–drug conjugate, is being investigated in CD22-positive cases, including in the ongoing phase II study NCT05412345 led by the University of California, San Francisco [19]. Other treatment strategies include blinatumomab, a bispecific T-cell engager with acceptable tolerability and safety, and CD19-directed CAR T-cell therapy, such as tisagenlecleucel, which uses autologous T lymphocytes genetically modified to target CD19 [20,21]. Preliminary data suggest promising response rates and acceptable tolerability, making these approaches potential options for patients who fail standard chemotherapy.

In recent years, only a few case reports describing similar scalp or head and neck presentations have been published, although the clinical details differ from those of our patient. Recent reports have described atypical presentations in which the final diagnosis was established only after histopathological and immunohistochemical evaluation [9,13–16]. Kim et al. described a pediatric patient with B-LBL presenting as a worsening scalp mass that required surgical excision and reconstruction [14], while Fox et al. reported B-LBL manifesting as a solitary scalp mass in a young child [9]. Montazer et al. described primary cutaneous B-cell lymphoblastic lymphoma presenting as a solitary scalp mass in a female child [15]. Wang et al. reported precursor B-cell lymphoblastic lymphoma presenting with concurrent enlarging scalp and postauricular masses in an adolescent [16]. In contrast, the present case involved a solitary, slowly enlarging frontal scalp lesion referred for neurosurgical management, clinically resembling a benign subcutaneous mass. These reports collectively emphasize that persistent, progressive or atypical pediatric scalp lesions should not be regarded as invariably benign and should undergo histopathological verification.

Conclusion

This case highlights a diagnostically challenging presentation of an aggressive pediatric malignancy. Although cutaneous and subcutaneous involvement, particularly in the head and neck region, is a recognized manifestation of BCP-LBL, a solitary, slowly enlarging frontal scalp mass mimicking a benign surgical lesion remains uncommon. Awareness of this presentation and of the potentially dynamic course of the disease may prevent diagnostic delay, avoid ineffective surgery as definitive treatment, and prompt early histopathological verification followed by referral for oncological treatment.

Author contributions

Dominika Bardońska—data collection, literature search, manuscript writing, critical revision of the manuscript Tymon Skadorwa—data management, manuscript writing, critical revision of the manuscript Łukasz Hutnik—data management, literature search, critical revision of the manuscript. All authors read and approved the final version of the manuscript.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

No datasets were generated or analyzed during the current study.

Declarations

Ethical statement

The authors confirm that have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

Dual publication

The authors declare that this manuscript has not been published elsewhere and is not under consideration by another journal.

Competing interests

The authors declare no competing interests.