Skeletal Lesions and Adductor Compartment Mass: A Rare Presentation of Hairy Cell Leukemia

A 57-year-old male was diagnosed with hairy cell leukemia (HCL) based on bone marrow biopsy and immunophenotyping (positive for CD20, CD22, CD11c, CD25, CD103 and CD123). A week later, he presented for new complaints of right-sided hip pain of 3 days duration. On examination he was found to have low grade fever and laboratory work showed pancytopenia. For hip pain, he underwent MRI hip which showed a large heterogenous centrally necrotic mass measuring up to 12 × 12 cm within the adductor compartment of the right proximal lower extremity (Fig. 1a, b). Also, his CT chest/abdomen showed a sclerotic lesion in right pelvis, lytic lesions in thoracic spine and a splenic space occupying lesion (Fig. 1c, d, e). Initially, it was unclear if the thigh mass and skeletal lesions were the part of HCL or represent another disease altogether.

Fig. 1.

a, b MRI hip joint A (Coronal STR) and B (T1 axial) showing large heterogenous centrally necrotic mass measuring up to 12 × 12 cm within the adductor compartment of the right proximal lower extremity. c, d, e CT sagittal view showing multiple lytic lesions across the thoracic spine, a sclerotic lesion on right pelvic bone and a splenic lesion. f Jackson-Pratt Drain showing thick purulent drainage

Subsequently, he underwent USG guided pigtail drainage of the heterogeneous collection in the proximal right thigh and a multipurpose pigtail catheter was placed (Fig. 1f). Culture grew methicillin sensitive staphylococcus aureus (MSSA) for which he was prescribed 14 days of cefazolin. He is planned for a repeat evaluation of the abscess and to initiate cladribine once infection resolves.

Skeletal involvement in HCL is a rare condition. Only few cases have been reported till date [1]. In HCL, most common pattern of skeletal involvement is lytic lesions of the axial skeleton. The exact pathophysiology behind skeletal involvement in HCL is unknown. Demanes et al. postulated that TNF-alpha could be a possible reason for localized bone resorption [2]. With regards to prognosis, Filippi et al. did not find any prognostic implication of bone lesions in HCL [3]. Though existence of dual cancers at the same time is possible, but knowledge about this rare presentation could be helpful to restrict unnecessary laboratory studies especially in classical cases of HCL.

Other rare scenario of HCL presentation can be without cytopenia and splenomegaly [4]. Gray et al.’s case presented with skeletal lytic lesions but without splenomegaly and pancytopenia [5]. Atypical findings in immunocompromised conditions are always challenging to diagnose and investigate [6, 7]

Our case sends a strong message that proper investigation should be carried out to address all the symptoms of patient. In our case, hip pain which was initially thought to be related to skeletal involvement by HCL but was later found to be a necrotic pus collection. Proper drainage and antibiotic therapy before starting chemotherapy prevented a catastrophe in this case.

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All authors have seen the manuscript and agree to the content and data. All the authors played a significant role in the paper.

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Authors have no conflict of interest to declare.

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The article doesn’t contain participation of any human being and animal.