Spindle cell rhabdomyosarcoma displaying cd34 positivity: a potential diagnostic pitfall; report of two pediatric cases

Context Metaplastic carcinomas arising in association with benign sclerosing lesions (BSLs) are rare malignancies in which a neoplastic spindle cell proliferation can be recognized extending beyond the boundaries of the complex sclerosing lesion or papilloma. However, in cases in which the metaplastic carcinoma is of the low-grade fibromatosis-like type or is a low-grade adenosquamous carcinoma, distinction from the background BSL can be a significant challenge. Cytokeratin (CK) and/or p63 immunostains are helpful in confirming the diagnosis of metaplastic carcinoma, but the expression patterns of these markers in the stromal cells of BSLs have not been well characterized. Objective To characterize the expression patterns of CKs and p63 in BSLs. Design We evaluated the spindle cell component of 55 BSLs using CK 5/6, CK 903, CK MNF116, and p63. Results A total of 45 cases (81%) showed no staining for CKs or p63 in benign stromal cells. CK 5/6, CK 903, and p63 were positive in one case each. CK MNF116 stained spindle cells within 10 BSLs. No cases showed spindle cell reactivity for all 4 markers. Positive cases demonstrated very focal, weak staining of spindle cells; only 1 case showed focal, moderate CK staining. Spindle cell positivity was not associated with lesion type, growth pattern, spindle cell atypia, or mitoses. Conclusions These findings suggest that although the presence or absence of expression of CK 5/6, CK 903, and p63 may be useful to distinguish BSL from metaplastic carcinomas arising in this setting, CK MNF116 positivity may be a diagnostic pitfall.

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Spindle cell carcinoma of the palatine tonsil: report of a diagnostic pitfall and literature review

American Journal of Otolaryngology ◽

10.1016/j.amjoto.2007.02.006 ◽

2008 ◽

Vol 29 (2) ◽

pp. 123-125 ◽

Cited By ~ 13

Author(s):

Shujiro B. Minami ◽

Seiichi Shinden ◽

Taku Yamashita

Keyword(s):

Literature Review ◽

Cell Carcinoma ◽

Spindle Cell ◽

Spindle Cell Carcinoma ◽

Palatine Tonsil ◽

Diagnostic Pitfall

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Desmin expression in spindle cell lipomas: a potential diagnostic pitfall

Virchows Archiv ◽

10.1007/s00428-004-1085-2 ◽

2004 ◽

Vol 445 (4) ◽

pp. 354-358 ◽

Cited By ~ 22

Author(s):

Juan C. Tard�o ◽

Jos� A. Aramburu ◽

Carlos Santonja

Keyword(s):

Spindle Cell ◽

Diagnostic Pitfall

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Intraparotid schwannoma masquerading as primary spindle cell tumour of parotid: A diagnostic pitfall

Journal of Cytology ◽

10.4103/joc.joc_147_15 ◽

2017 ◽

Vol 34 (4) ◽

pp. 221 ◽

Cited By ~ 1

Author(s):

JennaB Bhattacharya ◽

Meeta Singh ◽

ShyamL Jain

Keyword(s):

Spindle Cell ◽

Cell Tumour ◽

Diagnostic Pitfall ◽

Spindle Cell Tumour

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Nodal mycobacterial spindle cell pseudotumor: A diagnostic pitfall

Case Reports in Clinical Pathology ◽

10.5430/crcp.v8n1p33 ◽

2021 ◽

Vol 8 (1) ◽

pp. 33

Author(s):

Daniel Christensen ◽

Esteban Gnass ◽

Guldeep Uppal

Keyword(s):

Lymph Node ◽

Mediastinal Mass ◽

Spindle Cell ◽

Immunosuppressed Patient ◽

Diagnostic Challenge ◽

Diagnostic Pitfall ◽

Diagnostic Confusion ◽

Inflammatory Pseudotumors ◽

Generalized Lymphadenopathy ◽

Benign Mass

Inflammatory pseudotumor (IPT) is a rare benign mass forming lesion that has been reported in virtually every organ, and can closely mimic spindle cell neoplasms. Mycobacterial spindle cell pseudotumor (MSP) represents a small proportion of IPT of the lymph node, which occur in immunocompromised patients, posing a diagnostic challenge. We report three cases of MSP involving two AIDS patients who presented with generalized lymphadenopathy, and one immunosuppressed patient with a mediastinal mass. Biopsy in these cases revealed effaced architecture replaced by proliferating fibrohistiocytic spindle cells, fibrosis and polymorphic inflammatory infiltrate. Inflammatory pseudotumors and other spindle cell neoplasms of the lymph node can show overlapping morphologic features, resulting in diagnostic confusion. A differential diagnosis of Mycobacterial spindle cell pseudotumor should be kept in mind when approaching localized or generalized lymphadenopathy in an immunocompromised patient.

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