Smooth Muscle Tumors

Pneumocystis carinii Toxoplasma gondii Cryptosporidia Strongyloides stercoralis Malignancies Kaposi s sarcoma Non-Hodgkin s lymphoma Smooth muscle tumors Lymphocytic interstitial pneumonitis Nonspecific interstitial pneumonitis Drug-induced pneumonitis... 

Anti-alpha Isoform actin (clone 1A4) (M) Dako 1 200 MWER Recognition of smooth muscle tumors and myofibroblastic differentiation... 

Epithelioid features are known to occur in smooth muscle tumors, usually as a focal finding but occasionally as the predominant pattern. Such tumors have previously been designated as leiomyoblastomas, but current information indicates that even relatively bland tumors in the soft tissue may have metastatic potential. Thus, the term epithelioid LMS is preferred for those lesions with any degree of mitotic activity and cellular atypia. 

Schurch W, Skalli O, Seemayer TA, et al. Intermediate filament proteins and actin isoforms as markers for soft tissue tumor differentiation and origin. I. Smooth muscle tumors. Am J Pathol. 1987 128 91-103. 

Bowman F, Gultekin H, Dickman PS. Latent Epstein-Barr virus infection demonstrated in low-grade leiomyosarcomas of adults with acquired immunodeficiency syndrome, but not in adjacent Kaposi s lesion or smooth muscle tumors in immunocompetent patients. Arch Pathol Lab Med. 1997 121 834-838. 

Fadare O, Liang SX. Epithelioid smooth muscle tumors of the uterus do not express CDla A potential immunohistochemical adjunct in their distinction from uterine perivascular epithelioid cell tumors. Ann Diagn Pathol. 2008 12 401-405. 

Moran CA, Suster S, Perino G, et al. Malignant smooth muscle tumors presenting as mediastinal soft tissue masses A clinico-pathologic study of 10 cases. Cancer. 1994 74 2251-2260. 

Some immunohistologic peculiarities exist in reference to smooth muscle tumors of the skin. Roughly 30% of dermal leiomyomas and leiomyosarcomas are... 

S-100 protein reactive, and a similar proportion of subcuticular tumors are labeled for CD57. It has been speculated that those findings reflect pilar-smooth muscular and vascular-smooth muscular differentiation, respectively. They have practical importance as well because of shared patterns of reactivity with peripheral nerve sheath tumors of the skin. Fortunately, few of the latter lesions are expected to exhibit positivity for myogenic markers, as seen in smooth muscle tumors. 

Another contentious issue concerns the aberrant expression of keratin and EMA in smooth muscle tumors. Although some authors have reported a high incidence of that phenomenon in general, with no particular reference to specific soft tissue sites,the authors experience indicates that cutaneous leiomyomas and leiomyosarcomas only rarely show the presence of epithelial markers. 

Miettinen M, Monihan JM, Sarlomo-Rikala M, et al. Gastrointestinal stromal tumors/smooth muscle tumors (GISTs) primary in the omentum and mesentery clinicopathologic and immunohistochemical study of 26 cases. Am J Surg Pathol. 1999 23 1109-1118. 

Yanase M, Ikeda LT, Ogata I, et al. Primary smooth muscle tumor of the liver encasing hepatobiliary cystadenoma without mesenchymal stroma. Am Surg Pathol. 1999 23 854-859. 

CD117 may help distinguish vaginal CISTs that mimic smooth muscle tumors. 

Several endometrial stromal tumor variants have been described (Fig. 18.18). These include the smooth muscle variant (also referred to as mixed endometrial stromal and smooth muscle tumor or stromo-myoma), fibromyxoid variant,sex cord variant, and variants including endometrioid glands or epithelioid cells. The key to understanding the immunophenotype of these tumors is that variant or metaplastic elements often lose the phenotype of endometrial stroma and acquire the phenotype of the corresponding metaplastic element. Therefore, the smooth muscle in a smooth muscle variant of endometrial stromal nodule expresses muscle markers (Fig. 18.18B) and is frequently CD10-negative. T20 endometrioid... 

Although only one primary uterine gastrointestinal stromal tumor (GIST) has been reported, rectal examples may occasionally be mistaken for fibroids. Spindle cell examples would then suggest leiomyoma or perhaps even leiomyosarcoma, and epithelioid varieties could mimic an epithelioid smooth muscle tumor, carcinoma. 

Oliva E, Clement PB, Young RH, et aL Mixed endometrial stromal and smooth muscle tumors of the uterus—A clinicopatho-logic study of 15 cases. Am J Surg Pathol. 1998 22 997-1005. 

Nucci MR, O Connell JT, Huettner PC, et ah h-Caldesmon expression effectively distinguishes endometrial stromal tumors from uterine smooth muscle tumors. Am J Surg Pathol. 2001 25 455-463. 

Oliva E, Young RH, Amin MB, et al. An immunohistochemical analysis of endometrial stromal and smooth muscle tumors of the uterus—A study of 54 cases emphasizing the importance of using a panel because of overlap in immunoreactivity for individual antibodies. Am Surg Pathol. 2002 26 403-412. 

Chu PG, Arber DA, Weiss LM, et al. Utility of CDIO in distinguishing between endometrial stromal sarcoma and uterine smooth muscle tumors An immunohistochemical comparison of 34 cases. Mod Pathol. 2001 14 465-471. 

Loddenkemper C, Mechsner S, Foss HD, et al. Use of oxytocin receptor expression in distinguishing between uterine smooth muscle tumors and endometrial stromal sarcoma. Am J Surg Pathol. 2003 27 1458-1462. 

Oliva E, Clement PB, Young RH. Epithelioid endometrial and endometrioid stromal tumors A report of four cases emphasizing their distinction from epithelioid smooth muscle tumors and other oxyphilic uterine and extrauterine tumors. Int J Gynecol Pathol. 2002 21 48-55. 

Vang R, Kempson RL. Perivascular epithelioid cell tumor ( PEComa ) of the uterus A subset of HMB-45-positive epithelioid mesenchymal neoplasms with an uncertain relationship to pure smooth muscle tumors. Am J Surg Pathol. 2002 26 1-13. 

Oliva E, Wang WL, Branton P, et al. Expression of melanocytic ( PEComa ) markers in smooth muscle tumors of the uterus An immunohistochemical analysis of 86 cases. Mod Pathol. 2006 19 191A. 

Bodnet-Adlet B, Bodnet K, Czerwenka K, et al. Expression of pi 6 protein in patients with uterine smooth muscle tumors An immunohistochemical analysis. Gynecol Oncol. 2005 96 62-66. 

Smooth muscle tumors Peripheral nerve sheath tumors Paraganglioma Solitary fibrous tumor Follicular dendritic cell tumor Langerhans cell histiocytosis Secondary tumors... 

Actin (smooth muscle) Smooth muscle tumors Myoepithelial and myofibroblastic tumors Smooth muscle cells, myoepithelial cells, myofibroblasts... 

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