Pulmonary mycobacterial spindle cell pseudotumor in a lung transplant patient: progression without therapy and response to therapy

Abstract

Mycobacterial spindle cell pseudotumor (MSP) represents a rare, non-malignant, mass-forming reaction to various mycobacterial infections, typically occurring in immunocompromised patients. It is characterized by the proliferation of spindle-shaped fibrohistiocytic cells without the formation of epithelioid granulomas. Without staining for acid-fast bacilli, histological distinction from other spindle cell lesions, including malignancy, can be difficult. Most of the MSP cases reported in the literature have involved lymph nodes, skin, spleen, or bone marrow, but rarely involve the lung. MSP predominately occurs in patients who are immunosuppressed. We present a patient with MSP of the transplanted lung caused by non-tuberculous mycobacteria, in whom both the natural course of the untreated pseudotumor as well as the response to antimycobacterial treatments were observed.

Nodal mycobacterial spindle cell pseudotumor: A diagnostic pitfall

“…McGoldrick et al 2010 [10] 44M Lymph node (mediastinum) M. microti Steroid and azathioprine treated oral lichen planus Ilyas et al 2011 [45] 63M Nasal cavity MAC** Treated DLBCL☨ Yeh et al 2011 [9] 55M Skin M. chelonae Steroid treated scleroderma Alves et al 2012 [46] 28M Liver MTB*** AIDS Philip et al 2012 [7] 51F Lung MAI* AIDS Sideras et al 2013 [47] 42M Plantar fascia No culture HIV Ohara et al 2013 [6] 83M Nasal cavity MAI* HIV (Table 1 continued on page 37.) Rahmani et al 2013 [4] 79M Skin MAC** Solid organ transplant, Immunosuppressive therapy Holmes et al 2014 [48] 58M Skin M. chelonae None Ismail et al 2015 [49] 69M Brain MAI* Steroid treated sarcoidosis Franco et al 2015 [50] 69F Lung MAC** Solid organ transplant (lung), immunosuppressive therapy Lim et al 2016 [51] 66M Brain MAC** Steroid treated sarcoidosis Coelho et al 2017 [15] 13M Lymph node M. genavense Stem cell transplant, immunosuppressive therapy Thwaites et al 2018 [52] 88M Bone M. chelonae Diabetes Fonda-pascual et al 2018 [53] 50M Skin (penis) MAI* Combined immunodeficiency Dhibar et al 2018 [54] 38M Lymph node MTB*** AIDS Boylan et al 2018 [55] 33M Lung No culture AIDS Boylan et al 2018 [55] 45M Lung MAC** HIV Boylan et al 2018 [55] 69F Lung No culture None Taneja et al 2020 [56] 34M Lymph node MAC** AIDS Furlan et al 2020 [13] 42F Mycobacterial pseudotumors not only cause clinical and diagnostic confusion but can also confound the clinical picture as seen in the second case. This case showed hepatic diffuse large B-cell lymphoma as well as nodal MSP.…”

Mycobacterium Spindle Cell Pseudotumor Caused by Mycobacterium xenopi: A First Described Association of a Rare Entity Presenting in the Lung

“…6 Without staining for acid-fast bacilli (AFB), histological distinction from other spindle cell lesions, including mesenchymal malignancies, can be difficult. 7…”