INTRODUCTION

我宛如掉進冰窟窿一樣，灰心喪氣，渾身冷得發(fā)抖。突然，門開了，白麗筠走了進來，高跟鞋篤篤篤地敲擊地面。我熱情地向她表示歡迎，不料從白麗筠的身后閃出一個戴黑面罩的男子，露出兩只恐怖的眼睛，一下子閃到我的身后。他的胳膊與我的胳膊扭絞在一起，我動彈不得，他卻騰出雙手搬著我的腦袋，猛地一擰，我的頭顱就掉了下來，好像瓜蒂熟透的西瓜那樣……

Although cytologic atypia and the aggressive growth of tumor cells can be found in some cases in the literature[4,9,10], infarction and atypical mitosis inside the tumor have never been reported so far. Herein, we report a case of MTMF in the buttock that mimicked some pseudo-malignant features, including infarction, atypical mitosis, infiltrative growth, and prominent cytologic atypia, making it difficult to ascertain whether the tumor was benign. The purpose of this report is to remind pathologists to be alert for this potential diagnostic pitfall.

CASE PRESENTATION

Chief complaints

A 49-year-old man was admitted to Jiangxi Provincial People’s Hospital (the First Affiliated Hospital of Nanchang Medical College, Nanchang, China) with a mass in his right buttock for 4 mo.

History of present illness

There was nothing significant about the patient’s present medical history.

History of past illness

The patient had a history of sacrococcygeal trauma 3 years before admission, and there were no other abnormalities.

采用焦慮(SAS)自評量表對所有患者進行焦慮情況評分,包括護理干預前、護理干預后一周、護理干預后兩周、出院前一周的評定。焦慮程度按100分制具體評分標準為:重度焦慮:大于70分;中度焦慮:61-70分;輕度焦慮:50-60分;不焦慮:小于50分。

Personal and family history

In terms of personal and family history, there was nothing of note.

Physical examination

There was no abnormality except the fullness in the right rectal wall found during the special anal examination.

Laboratory examinations

No obvious abnormality was found in the serum tumor markers.

Imaging examinations

Magnetic resonance imaging (MRI) showed a large, well-defined mass located slightly to the right in the center of the pelvic cavity between the left and right obturator muscles (Figures 1A and 1B). The mass appeared predominantly positioned in the area deep to the gluteus maximus, posterior to the pubic symphysis, underneath the bladder, and above the urogenital septum (Figures 1C and 1D). It displaced the prostate and seminal vesicle glands to the upper left (Figures 1E and 1F) and pushed the rectum and anal canal close to the left pelvic wall (Figure 1B). The mass displayed predominantly isointense T1 signal, which was related to the surrounding musculature (Figures 1A and 1C) and heterogeneous on fat-suppressed T1 (T1FS; Figures 1B, 1D, and 1E) and T2 (T2FS; Figure 1F) imaging. There was intralesional focal necrosis and perilesional edema (Figures 1E and 1F).

Mammary-type myofibroblastoma (MTMF) is a rare, benign mesenchymal neoplasm occurring outside the breast that was first described in 2001[1]. The histological morphology of the lesion resembles myofibroblastoma in the breast, which was first reported in 1987[2]. It is usually well-circumscribed, encapsulated or unencapsulated, and composed of haphazardly arranged fascicles of spindle cells admixed with various amounts of adipocytes in a collagenous, hyalinizing, or myxoid background[3,4]. In immunohistochemical (IHC) results, the spindle cells often characteristically express both cluster of differentiation 34 (CD34) and desmin (Des)[1,4,5]. Genetically, MTMF belongs to “the 13q/retinoblastoma (Rb) family of tumors”, which are featured by deletion or rearrangement of the 13q14 region, resulting in loss of the

gene and Rb protein expression[4,6,7]. MTMF was almost always reported as a benign mesenchymal neoplasm, except in three recurring cases[4,8], one of which recurred due to positive excision margins[8].

The mass was surgically excised. During surgery, it was found to be well-circumscribed and with an incomplete capsule and poor mobility, giving a clinical impression of a malignant tumor. Its upper margin reached the seminal-vesicle gland, and the outer edge closely adhered to the right part of the external rectal sphincter, levator ani, and puborectal muscles, but no nerve, vessel, or inguinal lymph node invasion was found.

注重過程性考核，有破有立，首先是破，革除傳統(tǒng)考核方式存在的積弊。以往教學中將考核都集中于期末考試，“一卷定乾坤”帶來了顯而易見的負面效應，最突出的就是不少同學平時不認真學習，而將注意力都集中于期末的死記硬背上，突擊或是良好的記憶力也能獲得高分。要杜絕這一現(xiàn)象，打破學生上課走神，人在課堂心不在課堂的現(xiàn)狀，唯有引入過程性考核，把學生注意力從只求期末考試通過轉移到關注日常的學習，積極參與課堂教學的各個互動環(huán)節(jié)，與老師教學改革相配合。

On gross examination, the mass was 13 cm × 12 cm × 8 cm in size, and covered by an incomplete capsule and the remnants of adipose tissue (Figure 2A). The cut surface showed a solid, firm-to-elastic, and yellow-pink appearance, with focal cystic degeneration and necrosis within the mass (Figure 2B). Histologically, the tumor had a definite capsule (Figure 3A); it was composed of short spindle- to ovalshaped cells and admixed with varying thick bundles of collagen and variable numbers of adipocytes (Figure 3B). The cells had eosinophilic cytoplasm with indistinct cell borders and had elongated nuclei with fine chromatin (Figure 3B). Hyaline (Figure 3C) and mucoid (Figure 3D) degeneration were visible within the tumor. Atypic and bizarre cells could be seen in some areas (Figure 3E). It is worth noting that mitotic figures (Figure 3F), even atypical mitosis (Figure 3G), and multiple necrotic foci and nuclear debris (Figure 3H) could be seen in the tumor. In addition, smooth muscle (Figures 3I and 3J) and skeletal muscle (Figures 3K and 3L) were invaded within and at the edge of the tumor. These morphological features are often reminiscent of malignant tumors and therefore pose a severe diagnostic challenge to pathologists.

IHC staining showed that these neoplastic cells were strongly positive for both CD34 and Des (Figures 4A and 4B), and had lost expression of Rb1 protein (Figure 4C). In addition, they showed positive expression of estrogen receptor, epithelial-membrane antigen, human homolog of murine double minute 2 (MDM2), and cyclin-dependent kinase 4 (CDK4) (Figures 4D-G). However, they were negative for S100, smooth muscle actin (SMA), signal transducer and activator of transcription 6 (STAT6), and CD117 (Figures 4H-K). The proliferation index of these neoplastic cells was about 5%, as shown by Ki-67 IHC staining (Figure 4L). Fluorescence

hybridization (FISH) confirmed the monoallelic and biallelic deletion of the Rb1 (Figure 5A) and no amplification of MDM2 (Figure 5B) in these neoplastic cells.

Preoperative diagnosis

The preoperative clinical diagnosis was malignant mesenchymal tumor of the pelvic cavity.

FINAL DIAGNOSIS

The buttock is a rare anatomical site for MTMF. Except for our case, only two cases have been reported in the buttock so far[1,14]. Moreover, in addition to the morphological characteristics described above, the mass in our case also simulated some characteristics of malignant tumors, including infarction, atypical mitosis, infiltrative growth, and cytological atypia. These can pose diagnostic traps for pathologists. Nonetheless, infiltrative growth and atypical cytological findings, including degenerative nuclei, polynuclei, hyperchromatic nuclei, and bizarre nuclei, have been reported in previous cases[4,9]. However, there are no reports of infarction or atypical mitosis in MTMF. This is the first report of these two pseudo-malignant features appearing simultaneously in the same case. It is unclear whether these phenotypes suggest that the tumor has a certain malignant potential. After all, the > 160 previous case reports feature only three relapses[4,8], although one of them was due to positive margins[8].

The patient was followed for 2.5 years by telephone and MRI, and no recurrence or metastasis was found. Figure 6 shows the follow-up MRI scan of the patient’s pelvic cavity, at 6 mo post-operation. T1-weighted image (T1WI; Figure 6A), T1FS image (Figure 6B), coronal T1WI (Figure 6C), coronal T1FS image (Figure 6D), sagittal T1FS image (Figure 6E), and sagittal T2FS image (Figure 6F) showed complete removal of the mass, with normal diffusion in the patient’s pelvic cavity. There were no abnormalities except the abnormal signals from the right acetabulum and femoral head, and the ischemic necrosis of the head was considered. The size and position of pelvic visceral organs, such as the prostate, seminal vesicle, and rectum, were normal, and the bladder was well filled.

由表2可知，精子頂體完整率均隨各組稀釋液保存時間的延長而呈下降趨勢，且各組在第6 d到第9 d精子頂體完整率下降較快。雖從第1 d開始A1組頂體完整率稍低于C組，但A1組與C組精子頂體完整率在各個相同時間點差異均不顯著(P>0. 05)。

TREATMENT

The patient did not receive any treatment after operation.

OUTCOME AND FOLLOW-UP

醫(yī)院財務管理質(zhì)量直接影響著醫(yī)院的正常運營，但是從實踐情況來看，醫(yī)院在財務管理上存在著不同問題。加上當前我國醫(yī)療水平逐漸提升，對醫(yī)院各項基礎設施有了更高的要求，醫(yī)院財務管理的內(nèi)容繁雜，存在較大難度。本文通過分析當前環(huán)境下醫(yī)院財務管理工作中存在的問題，具體探討改進醫(yī)院財務管理工作質(zhì)量的有效措施，促進醫(yī)院財務管理質(zhì)量的不斷提升。

DISCUSSION

MTMF, proposed as an independent entity in 2001, is a very rare, benign, mesenchymal tumor occurring outside the breast. So far, more than 160 cases have been reported[2,4,5]. Adults aged 40-60 years are predisposed to MTMF, with men predominating slightly[4]. The tumor has extensive anatomic distribution; the groin and inguinal regions might be the most common sites[4,5]. Clinically, MTMF usually presents as a painless, slowly growing mass. The lump is well-circumscribed, firm, and 1-34 cm in size, with a pale-yellow or grayish-brown cut surface[2-4]. Microscopically, the tumor is composed of short spindle and oval-shaped cells with eosinophilic cytoplasm and fine chromatin. In a few cases, the cells are epithelioid[4,9]. Cells are arranged irregularly or in a palisade pattern similar to schwannoma, with collagen bundles in the stroma[4,11]. Various adipocytes and mast cells are seen in the stroma as well[3,4]. The blood vessels in the interstitium seem to be less visible, surrounded by infiltrating lymphocytes. In some cases, the stroma can be accompanied by hyalinization or myxoid degeneration[12,13].

Based on the above pathological, IHC, and FISH results, the final diagnosis was MTMF.

This case report documents an MTMF with certain pseudo-malignant characteristics, including tumor infarction, atypical mitosis, aggressive growth patterns, and cytological atypia. Taken together, these characteristics pose a diagnostic pitfall that must be avoided. The purpose of this report is to alert pathologists if they encounter a tumor with these pseudo-malignant features and myofibroblastic differentiation, they must not forget that they need to rule out the diagnosis of MTMF first.

Other differential diagnoses including spindle cell liposarcoma, atypical spindle cell lipomatous tumor (ASCLT), and the “fat-forming” variant of solitary fibrous tumors (SFTs) should all be considered. Spindle cell liposarcoma, which belongs to the well-differentiated liposarcoma family, is composed of fibroblast-like spindle cells arranged in bundles plus lipomatous liposarcoma. The tumor cells express S100, MDM2, and CDK4 proteins; amplification of MDM2 can be detected

molecular genetics[15], which can distinguish this tumor from MTMF. ASCLTs consist of adipose-differentiated spindle cells, which are positive for S100 as well as CD34 on IHC[16], and can be differentiated from MTMF. Nevertheless, in terms of genetics, there is no MDM2 amplification but rather loss of Rb1 in 57% of ASCLT cases[16]. MTMF might need differential diagnosis from SFT, especially the “fat-forming” variant of the latter. Although SFTs share CD34-positive immunostaining with MTMF, they specifically express another sensitive marker, STAT6, which results from rearrangement of STAT6[17]. Moreover, FISH shows no Rb1 loss in SFTs.

CONCLUSION

Next, we will discuss differential diagnosis of MTMF. Like MTMF, cellular angiofibroma (CA) and spindle cell lipoma (SCL) have the same abnormal 13q/Rb genetic changes and morphological overlap and similarity, which suggest that MTMF, CA, and SCL might be tumors of the same lineage[6]. Nevertheless, these tumors have subtle differences in morphology. Unlike MTMF, CA is usually confined to the groin area, and contains a prominent component of round vessels in the stroma, often accompanied by vascular-wall fibrosis and hyalinization. Moreover, CA has few adipocytes, and has wispy rather than thick collagen[4,6,7]. Generally, the CA spindle cells are positive for vimentin and negative for Des and CD34. All of these findings are helpful for differential diagnosis of CA from MTMF. SCL and MTMF are both composed of spindle cells admixed with mature adipose tissue, and both share a CD34-positive immunophenotype[7]. SCL mainly occurs in the posterior shoulder and neck or the upper back[6,7]; contains more-consistent, ropey, refractile collagen bundles, and adipose tissue; and does not stain for Des while almost always expressing CD34[4]. However, the overlapping morphologies of SCL, CA, and MTMF, combined with shared genetic alteration, raises the point that these tumors might belong to a single spectrum of the 13q/Rb family rather than be distinct entities[4,6].

ACKNOWLEDGEMENTS

We thanks for Professor Jian Wang, who comes from the Department of Pathology, Affiliated Cancer Hospital of Fudan University, for providing assistance in diagnosis and immunohistochemical staining of Rb1 protein and thank Anbiping for providing

hybridization detection probes and technical support for detecting

and

genes.

FOOTNOTES

Zeng YF checked the section reading, made the final pathological diagnosis, reviewed the literature, and wrote the manuscript; Dai YZ collated the clinical data, prepared histological sections, and performed immunohistochemical and fluorescence

hybridization; Chen M prepared tissue samples and made preliminary diagnosis; and all authors read and approved the final manuscript.

The authors declare no conflicts of interest for this article.

Informed written consent was obtained from the patient for publication of this report and any accompanying images.

The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).

2．1 一般狀況 本研究在兒童保健門診現(xiàn)場調(diào)查，實際發(fā)放問卷600份，收回有效問卷578份，回收問卷的有效率為96.3%，其中男女比例為1.09∶1，按有無睡眠問題分為兩組，睡眠問題組211名,男嬰113名，女嬰98名，無睡眠問題組367名，男嬰188名，女嬰179名。

This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BYNC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is noncommercial. See: https://creativecommons.org/Licenses/by-nc/4.0/

China

Yuan-Feng Zeng 0000-0003-4174-3575; Yan-Zhi Dai 0000-0001-7115-5294; Min Chen 0000-0002-5345-0991.

本研究中急性腦血栓患者的基礎資料和觀察指標結合SPSS23.0軟件分析,計量資料應用平均值表示,計量資料和計數(shù)資料的組間分析結合t檢驗和卡方檢驗,P<0.05為差異顯著。

Wang JJ

Wang TQ

Wang JJ

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