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Cover page of the Journal of Health Sciences

 Table of Contents  
Year : 2021  |  Volume : 14  |  Issue : 3  |  Page : 384-386

Focal hematopoietic hyperplasia of the rib, a rare form of pseudotumor: Report of a case with review of literature

Department of Pathology, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India

Date of Submission11-Feb-2021
Date of Acceptance03-May-2021
Date of Web Publication30-Sep-2021

Correspondence Address:
Dr. Kavita Mardi
Set No 14, Type VI Quarters, IAS Colony, Meheli, Shimla, Himachal Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/kleuhsj.kleuhsj_22_21

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Focal hematopoietic hyperplasia is a rare and localized proliferation of the bone marrow to such a degree that it produces a tumor-like expansion and hence called a pseudotumor. It is a rare benign condition and only 11 cases of focal hematopoietic hyperplasia have been reported in the English literature so far. We report one such rare case of focal hematopoietic hyperplasia in the rib of a 53-year-old female and reviewed the relevant literature. Our patient presented with backache and palpable swelling in the rib. Radiologically, they all manifested as an expansive and radiolucent lesion and contained ill-defined areas of increased density or calcification. Histologically, all have been characterized by mixed areas of hypercellular marrow and fatty marrow. Treatment in our case was by wide marginal excision of the rib.

Keywords: Bone, focal hematopoietic hyperplasia, rib

How to cite this article:
Mardi K, Murugai P, Bhardwaj M. Focal hematopoietic hyperplasia of the rib, a rare form of pseudotumor: Report of a case with review of literature. Indian J Health Sci Biomed Res 2021;14:384-6

How to cite this URL:
Mardi K, Murugai P, Bhardwaj M. Focal hematopoietic hyperplasia of the rib, a rare form of pseudotumor: Report of a case with review of literature. Indian J Health Sci Biomed Res [serial online] 2021 [cited 2022 Aug 14];14:384-6. Available from: https://www.ijournalhs.org/text.asp?2021/14/3/384/327252

  Introduction Top

Focal hematopoietic hyperplasia (FHH) is a rare and localized abnormal proliferation of the bone marrow to such a degree that it produces a tumor-like expansion that can rarely involve the ribs. FHHs are mostly found incidentally at radiologic studies performed for other reasons. They are characterized by gradually enlarging osteolytic masses that involve the rib. To our knowledge, only 11 cases have been reported.[1],[2],[3],[4],[5],[6],[7],[8],[9],[10] We report an additional such case of FHH occurring in the hematopoietic marrow of a rib.

  Case Report Top

A 53-year-old female presented with backache and complaints of painless swelling over the right side of the chest. On clinical examination, a vague lump palpated on the right side of the chest. Clinically, the possibilities of lipoma and bone malignancy were suggested. On computed tomography, the chest lytic lesion over the right 5th rib was found. Skeletal survey did not reveal any other lytic lesion elsewhere. All the hematological parameters were within the normal limits. Excision of the right 5th rib was done. Intraoperatively, there was a tumor expanding the medial aspect of the rib measuring 3 cm × 3 cm. On gross examination, we received a resected specimen of the rib measuring 10 cm in length. Located 2 cm from one end and 5 cm from the other end, there was a globular expansile mass measuring 3 cm × 2.5 cm with smooth outer surface. Cut section of the mass was grey brown to tan brown with small cystic spaces. Cortex was thinned out but there was no cortical breach. There was no clear cut demarcation between the tumor and the adjacent bone marrow [Figure 1]. Microscopic examination revealed hypercellular marrow merging with fatty marrow [Figure 1] and [Figure 2]. Trilineage hematopoiesis was seen with normal maturation of erythroid, myeloid as well as megakaryocytic series. M: E ratio was normal with adequate megakaryocytes [Figure 3]. Both thick and thin trabeculae were seen. No atypical cells or abnormal areas were identified. Cortex was thinned out but there was no erosion of the cortex. The increased osteoclastic activity was not observed.
Figure 1: Gross specimen showing globular expansile mass with brown to tan brown color cut section with thinned out cortex

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Figure 2: Tumor comprise of hematopoietic bone marrow with interspersed adipocytes separated by both thick and thin bony trabeculae. (H and E, ×100)

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Figure 3: High magnification showing normal trilineage hematopoiesis. (H and E, ×400)

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  Discussion Top

FHH is a rare and localized proliferation of the bone marrow to such a degree that it produces a tumor-like expansion and hence called a pseudotumor. These tumors are considered nonneoplastic benign proliferative lesion in response to trauma or any other stressful condition. Some other author considers it a deviation from the adult of red-yellow marrow distribution, with an increase of the red marrow components. Edelstein proposed two mechanisms regarding the pathogenesis of marrow hyperplasia[1] One could be in response to trauma, inflammation or other stressful condition, and other could be preexisting developmental anomaly.

FHH is characterized by a solitary osteolytic and expansive bony lesion of the rib with a maximum size of 9zed by a solitary osteolytic and expansive bony lesiical, radiologic, and histologic features.[4] The age at detection of FHH in these patients ranged from 22–71 years. Rib was the comments site, followed by vertebra (2 cases) and one case in the frontal bone. In majority of the cases, FHH was detected as an incidental finding during investigation for other diseases. The patient presented with back pain in cases reported by Detti et al.[5] Afrose et al.[7] and our case. Palpable mass was the presenting symptom only in cases reported by Afrose et al.[7] and our case. In none of the cases reported so far, there was associated hematological abnormality.

On histological examination, FHH shows a mixture of hypercellular and fatty marrow. The cellularity was increased by approximately 50%–95%. In all of the previously reported cases, the marrow contained all hematopoietic cell lines (erythroid, myeloid, and megakaryocytic cells) and no morphologically abnormal cells, or metastatic carcinoma cells were seen. Bony tissue became osteoporotic at some parts (due to disruption and thinning of some of the bony trabeculae) and denser at other parts (due to thickening and distortion of trabeculae).[4]

In discussing the differential diagnosis of FHH, we should consider all benign or malignant lesions. Radiologic findings suggest some differential diagnoses for FHH including fibrous dysplasia, aneurysmal bone cyst, and plasmacytoma. From the aspect of histopathologic evaluations, chondrosarcoma and some other bony lesions with the manifestation of hematopoietic hyperplasia must also be considered among differential diagnoses. However, myelolipoma and some hematological disorders including thalassemia, chronic anemia, leukemia, and myelofibrosis also present with increased hematopoiesis, hyperplastic and fatty marrow, and thin bony trabeculae. Tumor-like hyperplasia of fat tissue and bone marrow, known as myelolipoma; is most frequently found in the adrenal gland.[4],[9] Myelofibrosis is differentiated with concurrent hyperplasia of three hematopoietic cell lines which does not match with our findings. In cases of thalassemia evidence of the bone involvement include widened marrow cavity, cortical thinning, and marrow hyperplasia due to severe hemolysis. Although the bony involvement of thalassemia is distinct from others with the medullary expansion of multiple bones (such as craniofacial bones, vertebrae, pelvic bones, and ribs) and frequently involves the skull. The posterior aspect of the ribs shows cortical expansion. The patient suffers from anemia and is expected to have clinical features of anemia, skeletal deformity, and hepatosplenomegaly. FHH is not associated with anemia and hepatosplenomegaly and none of the above-mentioned clinical features were present in our patient.[4],[8],[9]

In conclusion, it is important to consider FHH of the rib among the differential diagnosis of solitary expanding bony lesions of ribs and vertebrae, especially when fine-needle aspiration biopsy or small tissue biopsy specimens yield apparently normal marrow tissue and microscopic evaluation reveal mixed hyperplasia of marrow and fatty tissue.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Edelstein G, Kyriakos M. Focal hematopoietic hyperplasia of the rib–A form of pseudotumor. Skeletal Radiol 1984;11:108-18.  Back to cited text no. 1
Galindo LM, Soans S, Chiaramonte C, Garcia FU. Focal hematopoietic hyperplasia of the rib. Report of a case diagnosed by fine needle aspiration. Acta Cytol 1998;42:987-90.  Back to cited text no. 2
Bordalo-Rodrigues M, Galant C, Lonneux M, Clause D, Vande Berg BC. Focal nodular hyperplasia of the hematopoietic marrow simulating vertebral metastasis on FDG positron emission tomography. AJR Am J Roentgenol 2003;180:669-71.  Back to cited text no. 3
Lee KB, Kim BS, Cho JH. Focal hematopoietic hyperplasia of the rib. Skeletal Radiol 2002;31:175-8.  Back to cited text no. 4
Detti B, Scoccianti S, Cassani S, Cipressi S, Franzese C. A case of focal haematopoietic hyperplasia of a vertebral body and review of the modern literature. J Nucl Med Radiat Ther 2013;4:151.  Back to cited text no. 5
Mollahosseini R, Motaghi P, Dastmalchi A, Zahm H. Focal hematopoietic hyperplasia of the rib-A form of pseudo-tumor. Case report and review of articles. Int J Surg Case Rep 2020;66:228-32.  Back to cited text no. 6
Afrose R, Akram M, Alam MF, Khalid S, Naim M. Focal haematopoietic hyperplasia of rib, mimicking to fibrous dysplasia. Ann Pathol Lab Med 2015;2:106-10.  Back to cited text no. 7
Vijay M, Mridha AR, Ray R, Kinra P, Mishra B, Chandrashekhar HS. Focal hematopoietic hyperplasia of rib: A rare pseudotumor and review of literature. J Pathol Transl Med 2015;49:159-62.  Back to cited text no. 8
Jayasinghe SI, Sumithran E. Focal haematopoietic hyperplasia of the rib: A case report of this exceedingly rare entity. Pathology 2009;41:494-5.  Back to cited text no. 9
Yakoub KM, Zisakis A, Ughratdar I. Cranial Focal Nodular Haematopoietic Hyperplasia: A case report and literature review. J Clin Neurosci 2018;53:244-6.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3]


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