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Piloleiomyoma mistaken for postacne scarring.

Piloleiomyomas are benign, smooth muscle neoplasms arising from the arrectores pilorum muscles in the skin. They differ in size and number and are often cold and painful or sensitive to touch. Piloleiomyomas, though not exceedingly rare, may not be expected in the differential diagnosis for multiple skin nodules. We present a case of a piloleiomyoma that was initially diagnosed as postacne scarring.

Acne Vulgaris↗

Prevertebral muscle involvement in nasopharyngeal carcinoma.

PURPOSE: The purpose of this study is to evaluate the prevalence and prognostic significance of prevertebral muscle involvement in patients with nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: Between July 1990 and December 2001, 521 newly diagnosed patients with NPC treated at Koo Foundation Sun Yat-Sen Cancer Center (KF-SYSCC) were examined with magnetic resonance imaging (MRI) for evidence of prevertebral muscle involvement before treatment. Patients were staged according to the 1997 American Joint Committee on Cancer staging classification of NPC based on the physical exams and MRI findings. All patients received radiotherapy with or without chemotherapy. The association between clinical prevertebral muscle involvement and posttreatment outcomes (overall survival, locoregional recurrence, and distant metastasis) were evaluated using Cox regression model to adjust for other prognostic factors. RESULTS: Of 521 patients treated at KF-SYSCC, 181 (35%) patients were found to have prevertebral muscle involvement, one-third in those with Stage II/III tumors and two-thirds in those with Stage IV tumor. In multivariate analysis accounting for all previously known prognostic factors, prevertebral muscle invasion was associated with an increased risk for any recurrence (adjusted relative risk, 2.01; p<0.001), locoregional recurrence (adjusted relative risk, 2.69; p<0.001), and distant metastasis (adjusted relative risk, 2.25; p<0.001), and with a borderline significant increased risk for overall survival (adjusted relative risk, 1.44; p=0.10). CONCLUSIONS: Prevertebral muscle involvement is an independent prognostic factor for NPC recurrence.

Adolescent↗

Spindle cell pseudotumor due to Mycobacterium avium-intracellulare in patients with acquired immunodeficiency syndrome (AIDS). Positive staining of mycobacteria for cytoskeleton filaments.

A rare spindle-cell pseudotumor caused by Mycobacterium avium-intracellulare (MAI) that mimics a mesenchymal tumor, was recently reported (7,14). We report on three such pseudotumors in patients with the acquired immunodeficiency syndrome (AIDS), two involving lymph nodes and one involving the bone marrow. In the course of investigating the first-encountered example of this tumor for evidence of smooth-muscle origin of the spindle cells, it was noted that these cells stained positively for desmin by immunoperoxidase techniques (IPX), as did a variety of other cytoskeleton filaments of all sizes. Electron microscopic examination of one of these lesions revealed spindle cells containing lysosomes and large numbers of microorganisms compatible with MAI but no filaments or organelles suggestive of smooth-muscle cells. Further studies revealed that the typical lesions produced by MAI in patients with AIDS, namely aggregates of histiocytes or individual histiocytes laden with organisms, rather than the expansile spindle-cell pseudotumor, also strain strongly for cytoskeleton filaments, as do M. tuberculosis and Mycobacterium leprae. Awareness of the existence of this unusual manifestation of MAI infection in AIDS patients and its desmin positivity can avoid misdiagnosis of a primary or metastatic smooth-muscle neoplasm. The cell of origin appears to be the histiocyte.

Acquired Immunodeficiency Syndrome↗

Epithelioid leiomyosarcoma of the skin and subcutaneous tissue. Clinicopathologic, immunohistochemical, and ultrastructural study of five cases.

This report describes five cases of an unusual variant of malignant smooth-muscle neoplasm involving the skin and subcutaneous tissue characterized by a proliferation of predominantly round to oval epithelioid cells with abundant eosinophilic cytoplasm. Of the five patients, four were men, one a woman; ages ranged from 69 to 85 years (mean, 76.4). The size of the lesions varied from 1.2 to 2.5 cm; two were located in the scalp, two in the face, and one in the back of the neck. Immunohistochemical evaluation of the tumor cells showed immunoreactivity for actin and vimentin in all cases and negative labeling for desmin, S-100 protein, keratin, epithelial membrane antigen, HMB-45, factor VIII, and alpha-1-antichymotrypsin. Ultrastructural examination showed features of smooth muscle differentiation, that is, focal plasmalemmal densities, basement membrane material, and cytoplasmic filaments with focal condensations. All patients were treated by surgical excision and two also with post-operative radiotherapy. Two cases recurred after 1 year, requiring wide excision. A second recurrence from one of these cases showed the emergence of a highly anaplastic, pleomorphic spindle cell sarcoma; the patient died of unrelated causes, with evidence of persistent disease, after 2 years. In the remainder of cases, the patients were alive and well with no evidence of recurrence or metastasis from 2 to 6 years. Because of the unusual morphologic features of this variant of smooth-muscle tumor it may be confused with a variety of primary and metastatic neoplasms of the skin, including malignant melanoma, epithelioid sarcoma, and metastatic carcinoma. Epithelioid leiomyosarcoma should be recognized as a distinct morphologic variant of primary cutaneous smooth muscle neoplasm and should be considered in the differential diagnosis of epithelioid neoplasms in dermal and superficial soft tissue locations.

Actins↗

Rhabdomyoma of the orbit.

To our knowledge, this is the first fully documented case of an adult-type orbital rhabdomyoma in an 8-year-old white boy, which originated in the belly of the medial rectus muscle and grew into the anterior orbit to incorporate the trochlea. Incomplete excision resulted in recurrence; the lesion was misinterpreted as a rhabdomyosarcoma and exenteration was performed. The patient was free of disease 25 years later. Reexamination of original pathologic material showed the typical histology of an adult-type rhabdomyoma. Adult-type rhabdomyoma, the most differentiated tumor in a spectrum of benign and malignant striated muscle neoplasms, should be distinguished from fetal rhabdomyoma (also benign) and pleomorphic rhabdomyosarcoma, the malignant striated muscle tumor most likely to be confused with rhabdomyoma. An awareness of the benign nature of rhabdomyoma (rhabdomyoma never evolves into a sarcoma) should prevent unnecessary radical surgery. The tumor can be adequately managed by a local excision that includes all the lobulations of tumor within a margin of normal tissue.

Child↗