Metastatic deposits of adenocarcinoma in bone marrow: A case report

INTRODUCTION

Commonly prevalent in organs such as the lungs, gastrointestinal system, pancreas, and prostate, adenocarcinoma is a form of malignant tumor that starts in glandular epithelial cells. Although there is enough evidence of metastasis to organs such as the liver, lungs, and brain, bone marrow involvement is rather rare and frequently signifies advanced-stage illness with a poor prognosis.^[1] Adenocarcinoma metastases in the bone marrow can manifest as non-specific hematological abnormalities such as pancytopenia, thrombocytopenia, or anemia, which frequently resemble hematological malignancies.^[2] The diagnosis might be difficult and necessitates a high index of suspicion in addition to comprehensive histological and immunohistochemical examinations because of its rarity and non-distinctive clinical appearance. This case report highlights the significance of bone marrow testing in patients with unexplained cytopenias and a history or suspicion of malignancy by highlighting an uncommon presentation of adenocarcinoma metastasizing to the bone marrow. Planning palliative care and proper administration depends on early diagnosis. There have been several reports of small cell carcinoma lung, gastric adenocarcinoma, breast, pancreatic, and prostate cancer spreading to bone marrow. It is uncommon for lung adenocarcinoma to involve bone marrow. We are presenting a case of adenocarcinoma, most likely lung, including bone marrow.

CASE REPORT

A 28-year-old man presented with a 45-day history of neck pain radiating to both shoulders. The pain worsened with neck movements and was described as a pressure sensation along the spine. For the past 1½ months, he experienced progressive weakness in the left lower limb, which began with tingling and numbness. He noted difficulty in holding his slippers during routine activities and developed weakness while attempting to rise from a squatting position. Notably, he did not report any leg pain or reduced touch sensation before this.

After becoming bedridden, he discovered that he was unable to sit up or move in bed. He also developed urinary and fecal incontinence. Subsequently, the patient reported bilateral upper-limb weakness. On examination, his temperature and pain sensation were within normal limits. However, there was hand grip weakness, bilateral proprioceptive impairment, and tenderness over the C4–C5 vertebral region. An magnetic resonance imaging (MRI) of the brain and spine revealed multiple T2 fluid-attenuated inversion recovery hyperintense lesions in the left upper frontal lobe, vermis, and bilateral cerebellar hemispheres. These lesions showed ring enhancement, raising suspicion for metastasis or an infectious etiology. A repeat MRI performed a week later demonstrated abnormal signal intensities with heterogeneous post-contrast enhancement in the cervical, thoracic, lumbar, and sacral vertebral bodies, suggesting widespread metastatic disease. There was compression collapse of the C6 vertebral body, spinal canal stenosis at C4–C5 and C5–C6, and associated compressive myelopathy. Additional degenerative changes in the lumbar spine were noted, including spinal canal stenosis and nerve root compression at L4–L5. The cerebellar hemispheres and vermis showed multiple subcentimetric ring-enhancing lesions of varying sizes, consistent with intracranial metastases. High-resolution computed tomography (CT) of the thorax revealed an ill-defined, heterogeneous soft-tissue lesion near the left hilum, causing an abrupt cutoff of the right middle lobe bronchus. Associated findings included collapse and consolidation, suggesting a malignant etiology with nodal and skeletal metastases. The right lower lobe showed diffuse reticular opacities, including intralobular and interlobular septal thickening. Other findings included mediastinal lymphadenopathy, a small left pleural effusion, and bilateral peribronchial cuffing.

Ultrasound of the abdomen showed a 6.2 mm calculus in the mid-pole of the left kidney. The liver and spleen measured 12.2 cm and 9.1 cm, respectively.

Bone marrow aspiration revealed clusters of metastatic cells in the cellular marrow. These were large cells with high nuclear–cytoplasmic ratios, open chromatin, and abundant basophilic cytoplasm arranged in gland-like patterns. Clusters of these tumor cells were seen alongside some hematopoietic elements [Figures 1 and 2]. A bilateral trephine biopsy from the posterior superior iliac spine showed hypercellular intertrabecular spaces infiltrated by metastatic tumor cells. These cancer cells formed glandular structures; in some areas, they appeared as solid clusters or single-cell linings. There was also evidence of desmoplasia and necrosis. The bony trabeculae appeared diffusely thinned, deformed, and irregular, with a “nibbled” appearance [Figure 3].

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Figure 1:

Bone marrow aspirates showing metastatic tumor cells showing gland formation. (magnification ×1000, Leishman stain). White arrow indicates metastatic tumour cells showing gland formation.

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Figure 2:

Bone marrow imprint smear showing infiltration of metastatic cells (magnification ×400, Leishman stain). White arrow shows infiltration of metastatic tumour cells.

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Figure 3:

Bone marrow biopsy showing metastatic infiltration of adenocarcinoma (magnification ×400, hematoxylin and eosin stain). White arrow indicates metastatic tumour cells showing gland formation.

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DISCUSSION

With 75% of cases happening in men and 51% occurring in industrialized nations, pulmonary carcinoma is currently the second most frequent malignancy worldwide. Its prevalence in males in India is 6.62/100,000.^[3] The majority of patients arrive with hemoptysis, dyspnea, coughing, and weight loss.^[4] The majority of the patients smoke regularly. Following an abnormal chest radiograph, the diagnosis is typically suspected and verified by CT-guided aspiration cytology or biopsy. CT scans of the chest and abdomen are used to determine the amount of cancer metastasis. Following bone marrow aspiration with metastatic deposits, our case presented with an intriguing presentation of bronchogenic adenocarcinoma, which was subsequently confirmed by bone marrow biopsy.

There were serious diagnostic challenges in this case. This patient had a history of neck pain that worsens with movement and weakness in the left lower limb, accompanied by involvement of the bladder and intestines. The patient also complained of bilateral arm weakness. An assessment of the bone marrow was conducted because the peripheral smear revealed leukoerythroblastic anemia with hemolysis. We diagnosed cancer lung with bone marrow metastases after discovering bone marrow deposits of adenocarcinoma using CT chest, revealing a right hilar mass, which was later verified by lesional aspiration as bronchogenic adenocarcinoma.

A case of lung adenocarcinoma involving bone marrow involvement was reported by Koluz et al.^[5] Rarely, bone marrow invasion accompanied by cytopenias or leukoerythroblastic anemia is one of the clinical issues associated with metastatic lung cancer. Although bone metastases typically appear later in the course of the disease, they can also be the initial sign of lung cancer in certain patients.^[6] According to Tzaveas et al., bronchogenic lung carcinoma has spread to the fifth metacarpal.^[7] The pulmonary veins are typically eroded by bronchogenic adenocarcinomas, which prevent them from entering the systemic circulation and cause widespread metastases.

Since the lesion was perihilar in position, a biopsy of the lung mass was not performed in this instance. Stage IV lung cancer is defined as involving bone marrow. Palliative chemotherapy was therefore used to treat the patient. This example emphasizes the significance of marrow examination in young patients with anemia, as marrow involvement is likely to be the early symptom of bronchogenic cancer.

CONCLUSION

This case highlights an unusual presentation of metastatic pulmonary adenocarcinoma in a young adult, where bone marrow involvement and neurological deficits were the initial manifestations. Bone marrow metastasis from lung adenocarcinoma is rare and can mimic hematological disorders or present with non-specific neurological symptoms due to spinal involvement. Early imaging and marrow evaluation are crucial in patients with unexplained cytopenias, progressive neurological symptoms, or back pain, especially in the absence of a known primary tumor.