This case represents the first documented instance of lymphoplasmacytic lymphoma involving marrow-containing submandibular heterotopic ossification, underscoring the importance of histopathological and molecular evaluation of excised calcified head and neck lesions even when clinical and radiologic findings suggest a benign process.
Key Findings
Background
A 77-year-old man presented with a calcified submandibular nodule that was initially interpreted as a calcified lymph node, with watchful waiting recommended.
The patient reported gradual enlargement and increasing discomfort during cervical rotation, prompting surgical excision.
Radiologic imaging demonstrated a well-circumscribed focus of soft-tissue ossification with no continuity to the mandible.
The lesion was the sole clinical manifestation of an otherwise occult lymphoproliferative disorder at initial presentation.
Results
Histopathological examination of the excised lesion revealed mature lamellar bone and marrow infiltrated by an atypical lymphoplasmacytic B-cell population.
The bone within the lesion was characterized as mature lamellar bone containing marrow spaces.
The marrow was infiltrated by an atypical lymphoplasmacytic B-cell population.
Immunohistochemical analysis demonstrated findings supportive of lymphoplasmacytic lymphoma.
PCR analysis was also performed and supported the diagnosis of lymphoplasmacytic lymphoma.
IgM kappa light-chain restriction was identified on immunohistochemical and molecular analysis.
Results
Subsequent hematologic evaluation confirmed systemic disease with a serum IgM paraprotein and sparse bone marrow involvement.
Serum IgM paraprotein was detected on hematologic workup following the histopathological diagnosis.
Bone marrow involvement was described as sparse.
The heterotopic ossification lesion served as the initial and sole clinical manifestation leading to the systemic diagnosis.
Discussion
This case represents the first documented instance of lymphoplasmacytic lymphoma involving marrow-containing submandibular heterotopic ossification.
The authors conducted a literature review of calcified soft-tissue lesions encountered in the head and neck region.
Heterotopic ossification is most commonly associated with trauma, surgery, or chronic inflammation.
The development of hematologic malignancies within heterotopic bone is described as 'exceedingly uncommon.'
No prior cases of lymphoplasmacytic lymphoma in submandibular heterotopic ossification were identified in the literature review.
Conclusions
The case underscores the importance of histopathological and molecular evaluation of excised calcified head and neck lesions even when clinical and radiologic findings suggest a benign process.
Clinical and radiologic features of the lesion suggested a benign calcified lymph node, leading to initial conservative management.
Only surgical excision and subsequent histopathological examination revealed the underlying malignancy.
Immunohistochemistry and PCR were both necessary to establish the diagnosis of lymphoplasmacytic lymphoma.
Without excision and pathologic evaluation, the occult lymphoproliferative disorder would have remained undetected.
What This Means
This research describes a rare and previously unreported medical case in which a 77-year-old man had a small, calcified lump in the left side of his neck below the jaw. Doctors initially thought it was a harmless calcified lymph node and recommended simply monitoring it. However, because the lump gradually grew and caused discomfort when the patient turned his head, it was surgically removed. When pathologists examined the tissue under a microscope and ran molecular tests, they discovered it was not just calcified tissue — it contained mature bone with marrow inside, and that marrow was infiltrated by cancer cells consistent with lymphoplasmacytic lymphoma, a type of slow-growing blood cancer. Further blood tests and bone marrow biopsy confirmed the cancer had spread elsewhere in the body at a low level.
This research suggests that calcified lumps in the head and neck region, even when they appear completely benign on imaging and clinical examination, can occasionally harbor unexpected and serious diagnoses. In this case, the calcified lump was the only outward sign of an otherwise hidden blood cancer. The finding highlights that simply watching and waiting, without eventually obtaining tissue for microscopic and molecular analysis, could result in a missed diagnosis.
The broader implication of this case is that surgeons and pathologists should consider thorough laboratory analysis — including immunohistochemistry and genetic testing — whenever calcified soft-tissue lesions from the head and neck are removed, regardless of how innocuous they appear beforehand. This approach may help detect occult (hidden) blood cancers or other unexpected conditions that would otherwise go undiagnosed until they become more advanced.
Loro L, Sandbakk F, Nybø C, Samstad E. (2026). Lymphoplasmacytic Lymphoma Involving Marrow-Containing Submandibular Heterotopic Ossification: A Case Report and Literature Review.. Head and neck pathology. https://doi.org/10.1007/s12105-026-01976-2