{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T10:27:23Z","timestamp":1787740043218,"version":"build-2784847793"},"reference-count":27,"publisher":"SAGE Publications","issue":"5","license":[{"start":{"date-parts":[[2026,3,15]],"date-time":"2026-03-15T00:00:00Z","timestamp":1773532800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2026,3,15]],"date-time":"2026-03-15T00:00:00Z","timestamp":1773532800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Int J Surg Pathol"],"published-print":{"date-parts":[[2026,8]]},"abstract":"<jats:p>\n                    Mycobacterial spindle cell pseudotumor is a rare manifestation of atypical mycobacterial infection. The process consists of a tumor-like proliferation of bland, spindle-shaped histiocytes that contain acid-fast-positive mycobacteria. Most patients are immunocompromised, and the lymph nodes are the most commonly involved site. The presentation of this process as an isolated aggressive osseous lesion is rare and conjures up a wide differential diagnosis, including neoplastic conditions. Accurate diagnosis of this entity is essential for proper management. We report a 79-year-old man with hypogammaglobulinemia who presented with an aggressively appearing lytic tibial lesion after sustaining a fall. Biopsy of the lesion revealed a mycobacterium-laden spindle cell pseudotumor without granuloma formation. The mycobacteria were visible on acid-fast Ziehl-Neelsen (AFB) stain and modified acid-fast (Fite) stain as well as PAS and GMS stains. PCR of the microbiology culture identified\n                    <jats:italic toggle=\"yes\">M<\/jats:italic>\n                    <jats:italic toggle=\"yes\">ycobacterium<\/jats:italic>\n                    <jats:italic toggle=\"yes\">kansasii<\/jats:italic>\n                    . Our report demonstrates that, although rare, mycobacterial spindle cell pseudotumor is a diagnostic consideration when encountering a lytic bone lesion in immunocompromised patients composed of cytologically benign, spindled histiocytes without characteristic caseating granuloma formation. Histochemical stains, including PAS, GMS, AFP, or Fit, are imperative to identify intracellular organisms.\n                  <\/jats:p>","DOI":"10.1177\/10668969261422273","type":"journal-article","created":{"date-parts":[[2026,3,16]],"date-time":"2026-03-16T06:15:58Z","timestamp":1773641758000},"page":"1341-1346","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":0,"title":["Mycobacterial Spindle Cell Pseudotumor Presenteing as an Aggressive Lytic Lesion in the Tibia in an Immunocompromised Patient"],"prefix":"10.1177","volume":"34","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8903-4658","authenticated-orcid":false,"given":"Hao","family":"Wu","sequence":"first","affiliation":[{"name":"1Department of Pathology, Yale School of Medicine\/Yale New Haven Hospital, New Haven, CT, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dieter","family":"Lindskog","sequence":"additional","affiliation":[{"name":"Yale School of Medicine\/Yale-New Haven Hospital, New Haven, CT, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"William","family":"Laskin","sequence":"additional","affiliation":[{"name":"Yale School of Medicine\/Yale-New Haven Hospital, New Haven, CT, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,3,15]]},"reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1093\/clinids\/5.4.657"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1038\/nri3211"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1136\/jclinpath-2017-204777"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1097\/00000478-199112000-00009"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1097\/00000478-199906000-00004"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1177\/1066896918770010"},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1097\/00000478-199410000-00010"},{"key":"e_1_3_2_9_2","doi-asserted-by":"publisher","DOI":"10.1111\/tid.12656"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1097\/DAD.0b013e3182120ae3"},{"key":"e_1_3_2_11_2","doi-asserted-by":"publisher","DOI":"10.1097\/00000478-199910000-00017"},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1097\/PAS.0000000000002234"},{"key":"e_1_3_2_13_2","doi-asserted-by":"publisher","DOI":"10.4103\/ijmy.ijmy_166_17"},{"key":"e_1_3_2_14_2","first-page":"9356243","article-title":"Laryngeal inflammatory pseudotumour secondary to Mycobacterium kansasii","volume":"2018","author":"Al-Zahid S","year":"2018","unstructured":"Al-Zahid S, Wright T, Reece P. Laryngeal inflammatory pseudotumour secondary to Mycobacterium kansasii. Case Rep Pathol. 2018;2018:9356243.","journal-title":"Case Rep Pathol"},{"key":"e_1_3_2_15_2","doi-asserted-by":"publisher","DOI":"10.5858\/2003-127-0554-PFOMKI"},{"key":"e_1_3_2_16_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jaad.2007.01.042"},{"key":"e_1_3_2_17_2","volume-title":"Giant cell tumor of bone","author":"Flanagan AML,F","year":"2019","unstructured":"Flanagan AML,F, O\u2019Donnell PG, Yoshida A. Giant cell tumor of bone. 5th ed. WHO Classification of Tumours Soft Tissue and Bone Tumours. International Agency for Research on Cancer; 2019.","edition":"5"},{"key":"e_1_3_2_18_2","volume-title":"Soft tissue and bone tumours World Health Organization classification of tumours","author":"Suumeijer AJHC-J","year":"2020","unstructured":"Suumeijer AJHC-J, A.M. Desmoplastic fibroma of bone. Soft tissue and bone tumours World Health Organization classification of tumours. 5th ed. 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