Surgical management of gingival plasma cell granuloma with histopathological and immunohistochemical confirmation through CD138 and kappa/lambda polyclonally: a case report

Abstract

Plasma cell granuloma (PCG) is a benign inflammatory lesion of reactive origin that is rarely found in the oral cavity. Accurate recognition is essential to differentiate it from malignant lesions and avoid overtreatment or unnecessary radical resections. We present the case of a 26-year-old female with no systemic history who presented with an asymptomatic, firm, erythematous gingival mass in the right upper posterior sextant. The lesion was associated with subgingival dental calculus and a deep carious lesion involving the first premolar and first molar. Treatment included complete surgical excision, extraction of both teeth, and bone curettage. Histopathological examination confirmed PCG, while immunohistochemistry showed CD138 positivity (70%) and polyclonal Kappa/Lambda expression, excluding monoclonal neoplastic restriction. At the 2-month follow-up, healing was satisfactory without recurrence. Histopathological and immunohistochemical evaluation provides a definitive diagnosis, and conservative surgical management is curative.

Introduction

Plasma cell granuloma (PCG) is a rare, benign, chronic inflammatory lesion that is purely reactive and non-neoplastic in nature [1–3]. Although it can develop in various anatomical sites—with the lung being the most commonly documented site [4]—its occurrence in the oral cavity is extremely rare [1, 5].

Accurate recognition of this condition is crucial to avoid misdiagnoses that could lead to excessive oncological treatment or unnecessary radical resections, or to suboptimal management that could result in recurrence [1, 5]. The objective of this case report is to present an unusual case of gingival PCG in a female patient, providing a detailed description of its surgical management, its microscopic features, and the relevance of the immunohistochemical profile (CD138 and Kappa/Lambda) as tools for differential diagnosis.

This case report was prepared in accordance with the CARE guidelines, and the completed CARE Checklist is provided as Supplementary Material.

Case report

A 26-year-old female patient with no significant systemic history—including the absence of systemic diseases—came to the dental office complaining: ‘I have a small lump on my gum; when I bite it, it bleeds.’

Intraoral clinical examination revealed an exophytic, asymptomatic mass with an erythematous brown color, a smooth surface, firm consistency on palpation, and a tendency to bleed, located on the interproximal gingiva of the right posterior superior region, extending from the first right upper premolar to the first right upper molar. The size of the lesion was 15 × 8 × 6 mm. Additionally, a deep carious lesion with extensive destruction of the coronal structure, involving the occlusal and distal surfaces, was observed in both dental specimens; furthermore, in the center of the cavities, a proliferating, lobulated, exophytic mass was identified, corresponding to the invagination of hyperplastic interdental tissue as a result of the loss of continuity of the proximal wall (Figs 1 and 2). The periapical radiographic examination showed no evidence of alveolar bone resorption.

The therapeutic management consisted of performing, under infiltration local anesthesia (4% articaine with epinephrine 1:100 000), a complete surgical excision of the lesion using a No. 15c scalpel, from the pedunculated base to the interproximal area of the upper right first premolar and first molar, ensuring adequate surgical margins (Fig. 3). The excised biopsy specimen measured 18 × 10 × 8 mm. Following tissue removal, subgingival dental calculus was observed on the affected teeth. It was determined that the extent of the carious lesion in both upper right teeth was too extensive and deep to restore; therefore, it was decided to extract both teeth, followed by bone curettage. The specimen was fixed in 10% formalin and sent to pathology. The site was closed with 6–0 polypropylene monofilament simple sutures. Amoxicillin 750 mg every 12 hours for 7 days, ibuprofen 600 mg every 8 hours for pain relief, and rinses with 0.12% chlorhexidine digluconate for 15 days was prescribed.

Histopathological analysis revealed a PCG (Fig. 4). Immunohistochemical evaluation showed marked positivity for CD138, with both cytoplasmic and membrane expression in 70% of the accompanying cells, confirming a predominance of the plasma cell lineage (Fig. 5); likewise, analysis of kappa and lambda light chains revealed positive polyclonal expression in these plasma cells. Confirmation of the reactive and inflammatory nature of the cellular infiltrate through this pattern of immunomarkers rules out neoplastic clonality (Figs 6 and 7).

The sutures were removed 15 days after the surgery. At the 3-month follow-up, adequate healing was observed, with no signs of inflammation, infection, or complications.

Discussion

The identification of PCG in the gingiva is an exceptional clinical finding due to its rarity in the oral cavity [1]. Although its exact etiopathogenesis remains a subject of debate, the current literature agrees that it corresponds to an exacerbated proliferative process driven by three interconnected mechanisms: chronic irritation from local microtrauma, persistent antigenic stimulation by biofilm components, and a disproportionate local immune response involving plasma cell chemotaxis [4, 5].

In this case, the interproximal location of the lesion served as a site for food retention and the accumulation of subgingival calculus. This persistent chronic injury correlated microscopically with the marked reactive changes observed in the epithelium (acanthosis, papillomatosis, and spongiosis), as well as with the fascicular proliferation of fibroblasts and myofibroblasts in the chorion, which reflect an attempt at organized tissue repair in response to sustained biological aggression.

When comparing this case with the scientific literature, a strict epidemiological and clinical concordance is observed. The patient’s age (26 years) is consistent with this condition’s predilection for young adults in their first three decades of life [5]. The smooth, brown-erythematous tissue appearance, firm consistency, and asymptomatic nature are consistent with global reports, in which pain is absent unless there are coexisting foci of severe ulceration or secondary infection [6, 7].

PCG can be mimicked by common reactive hyperplasias, such as pyogenic granuloma and peripheral ossifying fibroma, or malignant plasma cell disorders, including extramedullary plasmacytoma and multiple myeloma with maxillofacial manifestations [5, 7]. An accurate diagnosis of this entity is absolutely dependent on detailed microscopic analysis [4, 8]. However, to rule out any morphological overlap, immunohistochemistry stands as the decisive pillar of this study. Intense cytoplasmic and membrane positivity for CD138 in 70% of the accompanying cells categorically confirmed the plasma cell lineage of the lesion. However, the decisive factor was the analysis of light chains; the detection of kappa and lambda chains in the tissue absolutely ruled out monoclonal restriction (a characteristic of malignant neoplasms), confirming that the analyzed tissue was the direct result of a reactive and benign immune response [6, 9]. Figure 8 demonstrates polyclonally—the coexpression of both light chains—which is considered the primary molecular feature that distinguishes PCG from conditions such as multiple myeloma or extramedullary plasmacytoma, thereby enabling appropriate surgical management. This molecular distinction prevented misclassifications and avoided the unnecessary use of cytotoxic anticancer regimens or mutilating maxillofacial resections, ensuring that the conservative treatment administered was entirely curative [6].

The optimal treatment plan consisted of complete surgical excision. This technique has been successfully implemented in other similar clinical cases reported in the literature [2, 3, 5]. Although the risk of PCG recurrence is extremely low, it is advisable to implement a protocol for periodic clinical follow-up to promptly detect any signs of local recurrence, balancing the preservation of periodontal tissues with biological control of the condition.

Conclusion

Gingival PCG is a rare benign condition that poses a challenge due to its ability to mimic malignant neoplasms. A histopathological evaluation, supplemented by immunohistochemical profiling, CD138 staining, and demonstration of Kappa/Lambda polyclonally, can be considered definitive tools for establishing an accurate diagnosis. The combination of removing the lesion and extracting the affected ODs was effective as a definitive therapeutic solution.

Author contributions

Mario Alberto Alarcón-Sánchez (Writing—review & editing, Writing—original draft, Visualization, Validation, Supervision, Methodology, Formal analysis, Conceptualization), Eder Javier Martínez-González (Writing—review & editing, Writing—original draft, Visualization, Validation, Supervision, Methodology, Formal analysis, Conceptualization), Gustavo Eder González-Alvarez (Writing—review & editing, Writing—original draft preparation, Visualization, Validation, Supervision, Formal analysis, Conceptualization), Enrique Felichi Olivos-Navarro (Writing—review & editing, Writing—original draft, Visualization, Validation, Supervision, Formal analysis, Conceptualization), Miguel Angel Robles-García (Writing—review & editing, Writing—original draft, Visualization, Validation, Supervision, Formal analysis, Conceptualization), Lilibeth-Stephania Escoto-Vasquez (Writing—review & editing, Writing—original draft, Visualization, Validation, Supervision, Formal analysis, Conceptualization), Artak Heboyan (Writing—review & editing, Writing—original draft, Visualization, Validation, Supervision, Formal analysis, Conceptualization), and Sarah Monserrat Lomelí-Martínez (Writing—review & editing, Writing—original draft, Visualization, Validation, Supervision, Methodology, Formal analysis, Conceptualization)

All authors have read and agreed to the published version of the manuscript.

Supplementary material

Supplementary material is available at Journal of Surgical Case Reports online.

Conflicts of interest

All authors report no relevant conflicts of interest for this article.

Funding

None declared.

Data availability

The data supporting the findings of this study are available from the corresponding author upon reasonable request.

Patient informed consent

The study participant provided informed written consent prior to study enrollment.

CARE Checklist (2016) statement

The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).

References