Indian Journal of Cancer Medknow Publications on behalf of Indian Cancer Society ISSN: 0019-509X EISSN: 1998-4774 Vol. 47, Num. 4, 2010, pp. 485-486

Indian Journal of Cancer, Vol. 47, No. 4, October-December, 2010, pp. 485-486

Letter to Editor

Solitary plasmacytoma of the rib: A rare cytological detection

L Pattanayak¹, S Samantaray², N Rout²

¹ Department of Radiation Oncology, A. H. Regional Cancer Centre, Cuttack, India
² Department of Oncopathology, A. H. Regional Cancer Centre, Cuttack, India

Correspondence Address:
L Pattanayak
Department of Radiation Oncology, A. H. Regional Cancer Centre, Cuttack
India
lucypattanayak2007@yahoo.co.in

Code Number: cn10120

PMID: 21131776

DOI: 10.4103/0019-509X.73566

Sir,

Plasma cell neoplasms are disorders arising from the proliferation of a single clone of B-cell lymphocytes, 3% of which present as solitary lesions of bone or soft tissue.^[1] Solitary plasmacytoma most frequently involves the vertebrae or pelvic bones.^[2] Fine-needle aspiration cytology (FNAC) has been used as a first line investigation. We report a rare case of solitary plasmacytoma of the rib where a diagnosis was distinctly made on cytology.

A 60-year-old man presented with a history of increasing pain over the right side of the chest since 6 months. There was no history of trauma or tuberculosis. Physical examination revealed an oval swelling on the right side of the chest over the fourth rib, about 3 Χ 3 cm, firm and tender. A radiograph of the chest revealed a single, well-defined osteolytic lesion of 2 Χ 2 cm over the fourth right rib. Laboratory evaluation showed Hb 8.0 gm%, erythrocyte sedimentation rate 60 mm at the end of the first hour, and serum Ca ⁺² 6.0 mg%. FNAC from the rib was done and cytologic smears stained with Papanicolaou revealed multiple plasma cells both typical and atypical, arranged in sheets. Binucleated plasma cells with eccentric nucleus, characteristic cartwheel appearance along with prominent nucleoli, perinuclear halo, and abundant cytoplasm were also seen. The cytologic picture was highly suggestive of plasmacytoma [Figure - 1] and [Figure - 2]. Bone marrow aspiration revealed normocellular marrow, no systemic myelomatosis with myeloid:erythroid ratio (M:E) of 2:1. Serum electrophoresis showed a distinct M-band suggestive of multiple myeloma. Urinary Bence Jones protein was negative and a skeletal survey inclusive of radiograph of the skull, spine, and pelvis revealed no abnormality confirming the diagnosis of solitary plasmacytoma of the rib. The only two differential diagnoses on cytology include metastatic carcinoma and osteoblasts in case of bony lesions. In metastatic carcinoma, clusters of cells in acinar or glandular pattern with features of malignancy are seen, whereas osteoblasts can be differentiated by the absence of typical clear cytoplasm or perinuclear halo as seen in plasmacytomas. Knowing the radiosensitivity of the tumor, the patient was treated with radiation, 30 Gy in 10#(fractions), 3 Gy/#(fraction) over a period of 5 weeks. Eight months posttreatment, he was locoregionally controlled.

Woodruff et al,^[2] defined solitary plasmacytoma of bone as a solitary osteolytic lesion without any evidence of myelomatosis on bone marrow examination. Most frequently it affects the vertebral bodies, ribs, pelvis, skull, and sternum. The characteristic findings on X-ray are a single, well-defined osteolytic lesion with sharp borders, lack of bony sclerosis, and periosteal reaction.^[3] Histopathology shows multiple plasma cells as a thick sheet with scant intercellular stroma, extensive basophilic cytoplasm, round eccentric nucleus with cartwheel appearance, and perinuclear halo as seen in our case. The diagnosis is based on the solitary lesion in radiograph, plasma cells in biopsy, less than 5% plasma cells in bone marrow, and a negative urine test for Bence Jones protein.^[4] Here the cytology revealed a distinct picture of plasma cells with eccentric cartwheel-like nucleus, whereby a diagnosis of plasmacytoma was easily made, and further investigations ruled out multiple myeloma. Being highly radiosensitive, the local recurrence is less than 5% with conventional radiotherapy.

The present case of solitary plasmacytoma diagnosed on FNAC highlights the utility of FNAC and stresses that cytology can not only be used as an investigation tool, but also as a diagnostic modality.

References

Copyright 2010 - Indian Journal of Cancer

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