ALK-1 expression in inflammatory myofibroblastic tumor of the urinary bladder

Locally advanced solitary fibrous tumour of the prostate

Solitary fibrous tumours (SFTs) are rare mesenchymal neoplasms composed of spindle cells, most often occurring in the pleura. SFTs arising from the prostate are exceptionally rare, with only around 40 cases reported in literature to date. We report a man in his 60s who was referred to our clinic for elevated prostate-specific antigen and presented with mild obstructive lower urinary tract and defecatory symptoms. Prostate needle-core biopsy revealed neoplastic spindle cells that strongly expressed CD34. Cross-sectional imaging demonstrated a 12 cm locally advanced heterogeneous prostate mass with intravesical extension and mass effect on the anterior rectum. Radical cystoprostatectomy with orthotopic neobladder reconstruction was performed, and the diagnosis of primary prostatic SFT was made based on histological characteristics and immunophenotyping. We present diagnostic, clinical management and prognostic considerations in patients with primary prostatic SFT.

USP6-associated neoplasm as a tentative subset of postoperative spindle cell nodule

AIM

Postoperative spindle cell nodule (PSCN) is a pseudosarcomatous proliferative lesion of unclear molecular genetic origins.

METHODS AND RESULTS

We examined seven patients with PSCN, using routine haematoxylin-eosin (H&E) slide preparations and a series of immunostains. The latter targeted keratin, vimentin, α-smooth muscle actin (SMA), anaplastic lymphoma kinase (ALK [D5F3]), and other proteins. Ubiquitin-specific peptidase 6 (USP6) and anaplastic lymphoma kinase (ALK) gene rearrangements were also analysed by fluorescence in situ hybridization (FISH). There were histories of prior surgical intervention (n = 6) or trauma (n = 1) in all seven patients. All lesions were highly cellular and mitotically active spindle cell proliferations, with no cytologic atypia, nuclear pleomorphism, or aberrant mitoses. Immunohistochemical (IHC) staining disclosed focal, weak keratin positivity in two lesions, whereas vimentin (diffuse, strongly positive) and SMA (tram-track pattern) were present in each instance, and ALK (D5F3) was entirely negative. FISH analysis confirmed USP6 gene rearrangements in all seven cases, showing no ALK gene rearrangements. RNA sequencing results showed an MYH9::USP6 gene fusion in only one lesion (No. 6).

CONCLUSION

A subset of PSCN is marked by USP6 gene rearrangements, a genetic feature of nodular fasciitis (NF). Given its similarity to NF, a designation as USP6-associated neoplasm (UAN) seems reasonable, signifying a transient clonal neoplastic lesion.

Case report: Emergency management of spontaneous rupture of the inflammatory myofibroblastic tumor of the urinary bladder

Acute abdomen caused by spontaneous rupture of the inflammatory myofibroblastic tumor of the urinary bladder (IMTUB) is a rare clinical emergency of the urinary system.It is difficult to distinguish it from spontaneous rupture of bladder caused by other causes before surgery. An emergency case of spontaneous rupture of IMTUB was reported. A 57-year-old middle-aged woman was admitted to the hospital because of “acute lower abdominal pain for 5 hours”. No history of smoking and gross hematuria. The physical examination revealed visible abdominal tenderness as well as signs of shock. A pelvic CT scan shows a space-occupying lesion above the bladder with massive accumulation of blood. When the nature of the tumor could not be determined, emergency laparotomy and partial cystectomy were performed, and postoperative pathology confirmed cystitis myofibroblastic tumor. No local recurrence or distant metastasis of the tumor was observed during the regular follow-up period of 6 months. IMTUB should focus on prevention and treatment, with a combination of preoperative examination and postoperative pathology, and finally implement highly individualized treatment.

Pseudosarcomatous myofibroblastic proliferations of the urinary bladder are neoplasms characterized by recurrent FN1-ALK fusions

Pseudosarcomatous myofibroblastic proliferation is a descriptive term that designates a group of clinically indolent genitourinary lesions that most commonly arise in the urinary bladder. Given that pseudosarcomatous myofibroblastic proliferation may show morphologic overlap with inflammatory myofibroblastic tumor, the relationship, if any, between the two entities has been unclear. Moreover, pseudosarcomatous myofibroblastic proliferations are known to be positive for ALK immunohistochemistry in a subset of cases, although an inconsistent association with ALK rearrangement (ranging from 0 to 60%) has been reported. The objectives of this study were to determine the frequency of ALK rearrangement and to identify fusion partners using fluorescence in situ hybridization (FISH) and targeted RNA sequencing studies in a contemporary series of 30 pseudosarcomatous myofibroblastic proliferations of the urinary bladder, as well as to investigate ROS1 status by immunohistochemistry. ALK immunohistochemistry was positive in 70% (21/30) of pseudosarcomatous myofibroblastic proliferations; ROS1 immunohistochemistry was consistently negative (0/28). ALK rearrangements were detected by FISH in 86% (18/21) of cases, correlating with ALK immunohistochemical positivity in all but 3 cases. Of eight cases confirmed to be ALK rearranged by FISH, targeted RNA-sequencing detected FN1-ALK fusions in seven (88%) cases, which involved exons 20-26 of FN1 (5') and exon 18-19 of ALK (3'). In conclusion, ALK rearrangements are frequent in pseudosarcomatous myofibroblastic proliferations, typically involving exon 19, and FN1 appears to be a consistent fusion partner. Given the significant clinicopathologic differences between inflammatory myofibroblastic tumor and pseudosarcomatous myofibroblastic proliferation, our findings provide further support for classification of pseudosarcomatous myofibroblastic proliferation as a distinct clinicopathologic entity, and propose the alternate terminology "pseudosarcomatous myofibroblastic neoplasm of the genitourinary tract."

Urothelial carcinoma: variant histology, molecular subtyping, and immunophenotyping significant for treatment outcomes

Although urothelial carcinoma (UC) has been recognised as a homogenous disease entity until recently, it exhibits widely diverse histological variants. Recent studies have revealed that some histological variants may serve as markers of very high risk for advanced cancers and poor prognoses. Certain histological variants can generate a pathological T stage, which may result in unnecessary surgery. Though platinum based chemotherapy is the standard treatment, the use of immune checkpoint inhibitors (ICIs) for UC treatment has become a major trend in oncology. UCs showing specific histological variants have responded exceptionally well to chemotherapy and ICIs. Currently, molecular studies base molecular classification on gene expression profile signatures in order to make diagnoses or predict responses to chemotherapies and ICIs. Notably, some histological variants correlate with specific molecular subtypes. The usefulness of immunophenotyping for classification purposes was recognised only recently. Immunophenotypes are classified into three categories according to lymphocyte distribution in or around the cancer cell nest: desert, excluded, and inflamed. This immunophenotyping has been increasingly shown to be of value in predicting the response to ICIs. This review describes the morphological characteristics of histological variants as well as the advantages and limitations in determining them, with particular reference to clinical benefits. Subsequently, we describe the concept of molecular classification and immunophenotypes, and their morphological features, which are easily interpreted and amenable to daily practice via hematoxylin and eosin staining. We also consider the clinical advantages, limitations, and issues encountered while using these in routine clinical practice.

TERT promoter mutation analysis as a surrogate to morphology and immunohistochemistry in problematic spindle cell lesions of the urinary bladder

AIMS

Pseudosarcomatous myofibroblastic proliferations (PSMPs) of the urinary bladder are diagnostically challenging. Diagnostic difficulties are mainly due to frequent cytokeratin expression, variable ALK expression and worrisome morphological features suggestive of malignancy. Conversely, sarcomatoid urothelial carcinoma (UC) may show bland inflammatory myofibroblastic tumour (IMT)-like morphology. TERT promoter mutations are characteristic events in urothelial cancers, but have not been studied in PSMPs.

METHODS AND RESULTS

We compared histomorphological and immunohistochemical features and TERT promoter status in 16 PSMPs and 18 sarcomatoid UC. In a subset of PSMPs, RNA sequencing was performed. At least focal IMT-like morphology was seen in nine of 17 sarcomatoid UC. Atypical mitoses, differentiated urothelial component and heterologous elements were the most reliable distinguishing histomorphological features of sarcomatoid UC, if present. A panel of immunohistochemistry (IHC) including ALK (clone D5F3), p53 pattern, p63 and GATA3 reliably distinguished PSMP from sarcomatoid UC. GATA3 (P = 0.001) and p53 patterns (mutant versus wild-type; P < 0.001) were differentially expressed between PSMPs and sarcomatoid UC. Diffuse pancytokeratin staining was significantly associated with PSMPs (10 of 13) compared to four of 14 sarcomatoid UCs (P = 0.012). TERT promoter mutations were found in 17 of 18 sarcomatoid UC versus none of 16 PSMPs (P < 0.001). RNA sequencing revealed ALK genetic rearrangements in one of two ALK-positive and one of 10 ALK-negative PSMPs, which revealed a novel FN1/RET gene fusion.

CONCLUSION

Careful histomorphological analysis and differential IHC reliably distinguish the majority of PSMPs and sarcomatoid UC. In equivocal cases, TERT promoter mutation analysis and/or detection of ALK expression/rearrangements are valuable additional diagnostic adjuncts, strongly supporting sarcomatoid UC and PSMP, respectively.

A Rare Case of Inflammatory Myofibroblastic Tumor of the Prostate and Review of the Literature

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare type of soft-tissue neoplasm. IMT of the urinary tract is more common in the bladder and kidneys. Prostatic IMT is extremely rare.

CASE REPORT

We present a rare case of IMT of the prostate and a literature review on this condition. The patient was a 72-year-old man who presented with urinary symptoms. Transrectal needle biopsy of the prostate revealed prostatic adenocarcinoma with nodular hyperplasia. Radical prostatectomy revealed IMT without residual adenocarcinoma. On immunohistochemical examination, the tumor cells showed positive immunoreactivity for α-smooth muscle actin, CD10, CD34, and desmin but negative immunoreactivities for anaplastic lymphoma kinase (ALK), receptor tyrosine kinase (c-KIT), and S-100 protein. The patient underwent regular follow-up examination. No recurrence was observed 4 months after the diagnosis.

CONCLUSION

This was a case of IMT arising in the prostate. Pathologists should be aware of such an entity whenever they see spindle-cell lesions in the transrectal needle biopsy of the prostate.

A Rare Case of Inflammatory Myofibroblastic Tumor of the Prostate and Review of the Literature

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare type of soft-tissue neoplasm. IMT of the urinary tract is more common in the bladder and kidneys. Prostatic IMT is extremely rare.

CASE REPORT

We present a rare case of IMT of the prostate and a literature review on this condition. The patient was a 72-year-old man who presented with urinary symptoms. Transrectal needle biopsy of the prostate revealed prostatic adenocarcinoma with nodular hyperplasia. Radical prostatectomy revealed IMT without residual adenocarcinoma. On immunohistochemical examination, the tumor cells showed positive immunoreactivity for α-smooth muscle actin, CD10, CD34, and desmin but negative immunoreactivities for anaplastic lymphoma kinase (ALK), receptor tyrosine kinase (c-KIT), and S-100 protein. The patient underwent regular follow-up examination. No recurrence was observed 4 months after the diagnosis.

CONCLUSION

This was a case of IMT arising in the prostate. Pathologists should be aware of such an entity whenever they see spindle-cell lesions in the transrectal needle biopsy of the prostate.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Lack of expression of ALK and CD30 in breast carcinoma by immunohistochemistry irrespective of tumor characteristics

CD30 is a member of the tumor necrosis factor family of cell surface receptors normally expressed in lymphocytes, as well as some lymphomas, but has been described in other malignancies. Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that belongs to the insulin receptor superfamily, and is normally expressed in neural cells, but has been detected in several malignancies. There is conflicting data in the literature that describes the expression of these receptors in breast cancer, and the aim of this study is to test the expression of CD30 and ALK in a cohort of Middle Eastern patients with breast carcinoma.Cases of invasive breast cancer from the archives of AUBMC were reviewed over a period of 9 years, and the blocks that were used for immunohistochemical staining for ER, PR, Her-2/neu were selected. Immunohistochemical staining for CD30 (JCM182) and ALK (5A4 and D5F3) was performed.Two hundred eighty-four cases were identified (2 cases were male), with a mean age of 55 ± 12. CD30 and ALK expression was not seen in any of the cases.Our cohort showed complete negativity to both CD30 and ALK, adding to the conflicting data available in the literature, and more studies are needed to reliably identify a trend of expression of CD30 and ALK in breast carcinoma, especially in the Middle East.

ALK-negative urachal inflammatory myofibroblastic tumor in an elderly female: A case report

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare soft tissue lesion, originally reported in the lungs. Occurrence of the IMT was also documented in the digestive system, but rare in the urinary system, especially in the urachus, and little is presently known about IMT.

PATIENT CONCERNS

This study reported a very rare case of urachal IMT in an elderly female patient at the age of 77 who was diagnosed with a lower abdominal mass 2 months ago.

DIAGNOSIS

The preoperative diagnosis was urachal carcinoma, which was confirmed to be anaplastic lymphoma kinase (ALK) negative urachal IMT by postoperative histopathology and immunohistochemistry tests.

INTERVENTIONS

Laparoscopic radical urachal carcinoma resection and partial bladder resection was performed under general anesthesia, and the tumor was completely removed.

OUTCOMES

There was no recurrence and metastasis over 22 months of follow-up.

LESSONS

The urachal IMT occurs mainly in males and nonelderly people with ALK positive while in females with ALK negative. The most common clinical manifestations of urachal IMT are lower abdominal masses; it is very important to distinguish whether the tumor originates from the bladder or the urachus, because the surgical treatment options are completely different. Currently the complete surgical removal of the tumor is the best treatment option for urachal IMT. No other adjuvant therapy is required after operation. All urachal IMT after follow-up showed no recurrence and metastasis, suggesting a good prognosis. However, IMT has malignant potential and it requires a long-term close follow-up check.

Ureteral inflammatory myofibroblastic tumor: A case report and literature review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare soft-tissue neoplasm which has been described in a variety of locations. In the urogenital system, IMT predominantly occurs in the bladder and the kidney. IMT arising from the ureter is exceedingly rare and has been sporadically reported before.

PATIENT CONCERNS

We reported an extremely exceptional case of IMT arising from the ureteral submucosa in a 54-year-old man. The patient was hospitalized with the main complaint of intermittent and moderate left abdominal pain for 2 months.

DIAGNOSES AND INTERVENTIONS

Computed tomography scan revealed a nearly circular mass in the left upper ureter. Ureteroscopy showed that the ureteral lumen mucosa was smooth. However, the upper ureter was compressed and narrow. Renal dynamic imaging was performed and the measured glomerular filtration rate was 46.98 mL/min (right renal) and 9.77 mL/min (left renal), respectively. A retroperitoneoscopic radical nephroureterectomy was performed. The histopathologic examination revealed that the soft-tissue neoplasm was mainly composed of myofibroblastic spindle cells proliferation with mixed inflammatory infiltrate, containing lymphocytes, neutrophils, and eosinophils. On immunohistochemical staining, the tumor was positive for smooth muscle actin and Ki-67 (<1%+), indicating a confirmed diagnosis of ureteral IMT.

OUTCOMES

The patient recovered well with no occurrence of complications. At 3-year follow-up, there was no radiologic evidence of tumor recurrence or metastasis and the man was well.

LESSONS

Ureteral IMT is extremely rare and often asymptomatic, resulting in delayed diagnosis. Radiologic evidences may be suggestive of the diagnosis of IMT. However, it is necessary to make an accurate diagnosis in terms of histopathologic assessment. Complete lesion excision is the best therapeutic approach with rare recurrences and excellent survival.

Pseudosarcomatous myofibroblastic proliferations of the genitourinary tract are genetically different from nodular fasciitis and lack USP6, ROS1 and ETV6 gene rearrangements

AIMS

Pseudosarcomatous myofibroblastic proliferations of the genitourinary tract have a debatable relationship with inflammatory myofibroblastic tumour (generally lacking ALK rearrangement); however, they share several overlapping features with nodular fasciitis of soft tissue. As rearrangement of the USP6 gene has been recently recognised as a recurrent alteration in soft tissue nodular fasciitis, and several other alternative gene fusions have been recently recognised in inflammatory myofibroblastic tumour, the aim of this study was to investigate whether USP6, ROS1 or ETV6 rearrangements were present in these lesions (12 cases).

METHODS AND RESULTS

Fluorescence in-situ hybridisation analysis was performed by the use of bacterial artificial chromosome-derived break-apart probes against USP6, ROS1, and ETV6. Two cases with adequate genetic material from recent paraffin tissue blocks were also tested by use of a solid tumour gene fusion detection assay via next-generation sequencing, targeting >50 known genes involved in recurrent fusions. None of the genitourinary pseudosarcomatous myofibroblastic proliferations was found to harbour USP6 (0/12), ROS1 (0/8) or ETV6 (0/7) rearrangements, and no gene fusions were detected in two cases studied by sequencing.

CONCLUSIONS

Despite overlap in histological and immunohistochemical features between pseudosarcomatous myofibroblastic proliferation and nodular fasciitis, these tumours lack the recently recognised USP6 rearrangements that occur in nodular fasciitis, as well as alternative fusions found in ALK-negative inflammatory myofibroblastic tumours. At present, this diagnosis remains based primarily on clinical, histological and immunohistochemical features.

DICER1 mutation-positive giant botryoid fibroepithelial polyp of the urinary bladder mimicking embryonal rhabdomyosarcoma

Fibroepithelial polyps of the urinary tract are rare lesions. They occur mainly in the upper urinary tract of children. A high disease prevalence has been reported in families with pleuropulmonary blastoma. Here we present a case of a 46-year-old woman who presented with a giant botryoid fibroepithelial polyp of the urinary bladder. Histologically, the lesion showed prominent botryoid features with an embryonal rhabdomyosarcoma-like cambium layer lacking nuclear or cellular atypia. Immunohistochemical analysis ruled out rhabdomyoblastic differentiation. Next-generation sequencing was performed on the polyp tissue and revealed two pathogenic mutations in the DICER1 ribonuclease III (DICER1) gene (c.[5439G>T]; p.[Glu1813Asp] and c.[1525C>T]; p.[Arg509*]). Truncating DICER1 mutations, accompanied by characteristic "hotspot" mutations affecting the RNase IIIB domain of DICER1 are typically seen in DICER1-related lesions. Our findings indicate a role of DICER1 mutations in the pathogenesis of fibroepithelial polyps of the urinary tract.

Long-term effects of crizotinib in ALK-positive tumors (excluding NSCLC): A phase 1b open-label study

Crizotinib, an inhibitor of anaplastic lymphoma kinase (ALK), MET, and ROS1, is approved for treatment of patients with ALK‐positive or ROS1‐positive advanced non‐small‐cell lung cancer (NSCLC). However, ALK rearrangements are also implicated in other malignancies, including anaplastic large‐cell lymphoma and inflammatory myofibroblastic tumors (IMTs). In this ongoing, multicenter, single‐arm, open‐label phase 1b study (PROFILE 1013; NCT01121588), patients with ALK‐positive advanced malignancies other than NSCLC were to receive a starting dose of crizotinib 250 mg twice daily. Primary endpoints were safety and objective responses based on Response Evaluation Criteria in Solid Tumors version 1.1 or National Cancer Institute International Response Criteria. Forty‐four patients were enrolled (lymphoma, n = 18; IMT, n = 9; other tumors, n = 17). The objective response rate was 53% (95% confidence interval [CI], 28–77) for lymphoma, with 8 complete responses (CRs) and 1 partial response (PR); 67% (95% CI, 30–93) for IMTs, with 1 CR and 5 PRs; and 12% (95% CI, 2–36) for other tumors, with 2 PRs in patients affected by colon carcinoma and medullary thyroid cancer, respectively. The median duration of treatment was almost 3 years for patients with lymphoma and IMTs, with 2‐year progression‐free survival of 63% and 67%, respectively. The most common treatment‐related adverse events were diarrhea (45.5%) and vision disorders (45.5%), mostly grade 1. These findings indicate strong and durable activity of crizotinib in ALK‐positive lymphomas and IMTs. The safety profile was consistent with the known safety profile of crizotinib even with long‐term treatment.

Mesenchymal tumors of the prostate

Mesenchymal tumors of the prostate are rare but often cause considerable diagnostic difficulty when encountered. These may be either benign or malignant and can arise within the prostate gland or in adjacent tissues. This review covers prostatic stromal proliferations (prostatic stromal tumor of uncertain malignant potential and stromal sarcoma), solitary fibrous tumor, myofibroblastic proliferations, smooth muscle neoplasms (leiomyoma and leiomyosarcoma), gastrointestinal stromal tumor, schwannoma, rhabdomyosarcoma, sarcomatoid carcinoma, postradiation sarcoma, and mixed epithelial stromal tumor of the seminal vesicle. Differential diagnostic considerations are emphasized, including descriptions of helpful histological and/or clinical clues and the use of adjuvant diagnostic techniques.

Uterine inflammatory myofibroblastic tumor: more common than expected: Case report and review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm composed of spindled to epithelioid cells with prominent myxoid stroma and inflammatory infiltrate. It has a low but definite malignant potential. However, its management has never been standardized.

PATIENT CONCERNS AND DIAGNOSIS

We present the first case of uterine IMT laparoscopically treated. Moreover, we reviewed the English literature regarding uterine IMT published between 1987 and June 2017. A total of 72 cases of uterine IMT were included. Clinical and pathological characteristics, treatments and outcomes were recorded.

INTERVENTIONS AND OUTCOMES

A total laparoscopic hysterectomy with opportunistic bilateral salpingectomy was performed. Patient is free of disease at 6 months of follow-up.

LESSONS

Uterine IMT may be identified by anaplastic lymphoma kinase overexpression, its prognosis is usually good, complete excision seems to be effective to avoid relapse and mini invasive surgery seems to be effective and safe to treat uterine IMT. However, considering the age of women affected by disease, conservative management, or medical therapy could be taken in account to avoid surgical injuries and to preserve fertility.

Practical Applications of Immunohistochemistry in the Diagnosis of Genitourinary Tumors

Context.—

Pathologic diagnosis of tumors in the genitourinary system can be challenging based on morphology alone, particularly when diagnostic material is limited, such as in core biopsies. Immunohistochemical stain can be a useful tool to aid in the diagnosis.

Objective.—

To provide an update on practical applications and interpretation of immunohistochemical stains in the diagnosis of tumors in prostate, kidney, bladder, and testis. We particularly focus on difficult differential diagnoses, providing our insights in frequently encountered challenging situations. Commonly used immunohistochemical panels are discussed.

Data Sources.—

Review of literature and our own experience.

Conclusion.—

Immunohistochemical stain is a valuable tool in the diagnosis of genitourinary tumors when appropriately used.

Inflammatory Myofibroblastic Tumor in the Bladder: A Case Report

A 36-year-old male was referred to our department for further examination of asymptomatic gross hematuria emanating from a bladder tumor. Cystoscopy revealed a broad-based tumor 40 mm in diameter. Urinary cytology was negative. Preoperative magnetic resonance imaging suggested a muscle invasive tumor. Transurethral resection was performed, and the pathological findings revealed an inflammatory myofibroblastic tumor. We herein report a rare case of bladder inflammatory myofibroblastic tumor.

Inflammatory myofibroblastic tumour

While initially controversial, the proposal that a subset of inflammatory pseudotumours were myofibroblastic neoplasms is now acknowledged. Inflammatory myofibroblastic tumour is a spindle cell neoplasm of intermediate biological potential that may arise in a wide range of anatomic sites but has a particular propensity for the lung and abdominal soft tissues. Depending on its location, IMT may present with a variety of clinical symptoms and it may also express a variable pathologic phenotype, leading to a broad range of clinical and pathological differentials. Recent discoveries about the molecular signatures of IMT not only provide additional tools to assist in their diagnosis, they also point to possible therapeutic interventions that may transform the management algorithms for patients with this condition.

Inflammatory Myofibroblastic Tumor of the Urinary Bladder: A Case Report

An inflammatory myofibroblastic tumor (IMT) is a distinctive neoplasm composed of myofibroblastic and fibroblastic spindle cells, accompanied by inflammatory infiltration of plasma cells, lymphocytes, and eosinophils. IMTs rarely occur in the urinary bladder. It is important to distinguish this tumor from other malignant spindle cell tumors. Herein, we report a patient with an IMT showing muscle invasion, who underwent a transurethral resection of the bladder tumor and, at a later date, partial cystectomy. The resected tumor specimen revealed a proliferation of spindle-shaped cells on a background of plasma cells and lymphocytes. Immunohistochemical staining showed the tumor to be positive for anaplastic lymphoma kinase (ALK), smooth muscle actin, and vascular endothelial growth factor (VEGF). Such histopathological findings were indicative of an IMT, suggesting the use of inhibitors of ALK and VEGF as pharmacotherapy.

Clinicopathologic characteristics of intra-abdominal epithelioid inflammatory myofibroblastic sarcoma

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a rare subtype of inflammatory myofibroblastic tumor (IMT), and its clinicopathologic characteristics, immune phenotypes and molecular genetics are particular. Here we report a case of intra-abdominal EIMS. A male patient, aged 46 years, was admitted due to recurrent pain and distension in the abdomen for more than 10 days. Grossly, a nodular mass measuring 17 cm × 12 cm × 8 cm was observed, and it was grayish yellow and solid, had a fish-like cut surface, and tended to be well circumscribed with medium consistency. Microscopically, round to epithelioid cells were scattered in a mucinous and neutrophil-predominant inflammatory background, and the tumor cells had vacuolated nuclei, prominent nucleoli, and amphophilic or eosinophilic cytoplasm. Immunohistochemically, the tumor cells showed typical nuclear membrane staining for ALK, diffuse and strong cytoplasmic staining for CD30 and Vimentin. Split signals were detected by FISH using break-apart probes to ALK. The aggressive biological behavior of EIMS increases the risk of recurrence and metastasis, and thus the prognosis is poor. Surgical resection is the main treatment for EIMS, with radiation therapy or chemotherapy as a postoperative adjunct.

Nodular fasciitis of the vulva: a challenging histopathologic diagnosis supported by the detection of USP6 gene rearrangement

Nodular fasciitis involving the vulva on physical examination can mimic a Bartholin gland lesion, and histologically can have overlapping features with more ominous mesenchymal pathologies. We describe a case in which a 52-year-old perimenopausal woman presents with a vulvar mass. After an initial biopsy and later excision, the myofibroblastic lesion was noted to have areas of differing cellularity, with compact nodule formations at the periphery. Immunohistochemical staining showed lesional cells to be positive for desmin, estrogen receptor, progesterone receptor, and smooth muscle actin, and negative for CD34, ALK-1, myogenin, caldesmon, S100, and wide spectrum (Oscar) cytokeratin. Desmin is generally negative in this lesion type, but the positivity in this case was considered to be secondary to the origin of the myofibroblastic cells of the vulva. The morphologic pattern and immunophenotype favored a diagnosis of nodular fasciitis, however, the degree of hypercellularity and desmin positivity warranted further analysis. The diagnosis was supported with fluorescence in situ hybridization that demonstrated USP6 gene rearrangement. This highlights the necessity in certain challenging cases for ancillary molecular and/or cytogenetic analysis.

Genetics of Bladder Malignant Tumors in Childhood

Bladder masses are represented by either benign or malignant entities. Malignant bladder tumors are frequent causes of disease and death in western countries. However, in children they are less common. Additionally, different features are found in childhood, in which non epithelial tumors are more common than epithelial ones. Rhabdomyosarcoma is the most common pediatric bladder tumor, but many other types of lesions may be found, such as malignant rhabdoid tumor (MRT), inflammatory myofibroblastic tumor and neuroblastoma. Other rarer tumors described in literature include urothelial carcinoma and other epithelial neoplasms. Rhabdomyosarcoma is associated to a variety of genetic syndromes and many genes are involved in tumor development. PAX3-FKHR and PAX7-FKHR (P-F) fusion state has important implications in the pathogenesis and biology of RMS, and different genes alterations are involved in the pathogenesis of P-F negative and embryonal RMS, which are the subsets of tumors most frequently affecting the bladder. These genes include p53, MEF2, MYOG, Ptch1, Gli1, Gli3, Myf5, MyoD1, NF1, NRAS, KRAS, HRAS, FGFR4, PIK3CA, CTNNB1, FBXW7, IGF1R, PDGFRA, ERBB2/4, MET, BCOR. Malignant rhabdoid tumor (MRT) usually shows SMARCB1/INI1 alterations. Anaplastic lymphoma kinase (ALK) gene translocations are the most frequently associated alterations in inflammatory myofibroblastic tumor (IMT). Few genes alterations in urothelial neoplasms have been reported in the paediatric population, which are mainly related to deletion of p16/lnk4, overexpression of CK20 and overexpression of p53. Here, we reviewed available literature to identify genes associated to bladder malignancies in children and discussed their possible relationships with these tumors.

Current and proposed molecular diagnostics in a genitourinary service line laboratory at a tertiary clinical institution

The idea that detailed knowledge of molecular oncogenesis will drive diagnostic, prognostic, and therapeutic clinical decision making in an increasingly multidisciplinary practice of oncologic care has been anticipated for many years. With the recent rapid advancement in our understanding of the molecular underpinnings of genitourinary malignancies, this concept is now starting to take shape in the fields of prostate, kidney, bladder, testicular, and penile cancer. Such breakthroughs necessitate the development of robust clinical-grade assays that can be quickly made available for patients to facilitate diagnosis in challenging cases, risk-stratify patients for subsequent clinical management, select the appropriate targeted therapy from among increasingly diverse and numerous options, and enroll patients in advanced clinical trials. This rapid translation of basic and clinical cancer research requires a streamlined, multidisciplinary approach to clinical assay development, termed here the molecular diagnostics service line laboratory. In this review, we summarize the current state and explore the future of molecular diagnostics in genitourinary oncology to conceptualize a genitourinary service line laboratory at a tertiary clinical institution.

A primary inflammatory myofibroblastic tumor of the scapula in a child: imaging findings

Inflammatory myofibroblastic tumor (IMT) is an uncommon tumor characterized by inflammatory cell infiltration and differentiated myofibroblastic spindle cells. IMT was first described in the lung and retroperitoneum. Occurrence in bone has been well described in the maxilla and occasionally in the long bones in the adult population. We present a unique case of IMT arising primarily from the scapula in an 8-year-old patient, not described previously in the pediatric or adult literature. Imaging demonstrated an ill-defined and aggressive osteolytic lesion with cortical bone destruction associated with an important soft tissue component that extended into the adjacent muscles. Histologically, the tumor was composed of spindle and polygonal cells distributed in an inflammatory background with different proportions of plasma cells, lymphocytes, eosinophils and neutrophils. The absence of cellular atypia helped to differentiate this entity from malignant spindle cell tumors, and imaging could differentiate the tumor from the nontumoral inflammatory reaction.

Assessment of the potential diagnostic role of anaplastic lymphoma kinase for inflammatory myofibroblastic tumours: a meta-analysis

Objective

To assess the value of anaplastic lymphoma kinase for the diagnosis of inflammatory myofibroblastic tumours using a comprehensive meta-analysis.

Methods

We searched the related literature using electronic databases and manual searches. Approximately 454 cases from several countries were included in this analysis. The quality of studies included was assessed by QUADAS (quality assessment of studies of diagnostic accuracy). The diagnostic odds ratio (DOR), positive likelihood ratio (PLR), negative likelihood ratio (NLR), sensitivity and specificity were calculated to assess the role of anaplastic lymphoma kinase in the diagnosis of inflammatory myofibroblastic tumours. The overall test performance was summarised by an SROC (summary receiver operating characteristic curve). The heterogeneity and publication bias were analysed using Meta-regression and Deeks' test. All data were analysed by Stata 12.0 software.

Results

Eight studies were included according to our inclusion criteria. The overall results for the specificity, sensitivity, PLR, NLR, DOR and area under the curve (AUC) were 0.99 (95% CI 0.82-1.00), 0.67 (95% CI 0.46-0.83), 0.67 (95% CI 0.46-0.83), 60.6 (95% CI 3.3-1112.4), 0.33 (95% CI 0.19-0.60), 181 (95% CI 9-3684) and 0.95 (95% CI 0.93-0.97), respectively, while the specificity, sensitivity, PLR, NLR, DOR and AUC for bladder IMTs were 0.99 (95% CI 0.67-1.00), 0.86 (95% CI 0.58-0.96), 95.6 (95% CI 2.0-4616.2), 0.14 (95% CI 0.04-0.50), 671 (95% CI 16-28913) and 0.99 (95% CI 0.97-0.99), respectively.

Conclusion

The present meta-analysis indicated that anaplastic lymphoma kinase plays a significant role in the differential diagnosis of inflammatory myofibroblastic tumours, particularly for inflammatory myofibroblastic tumours of the urinary bladder.

Inflammatory myofibroblastic tumor of the thigh: presentation of a rare case and review of the literature

Inflammatory myofibroblastic tumors are uncommon neoplasms; presentation of these tumors in the lower extremities is extremely rare. We present a case of a 47-year-old male with fever, fatigue, and a slow-growing thigh mass. The inflammatory markers were elevated and the MR images showed a well-defined intermuscular lesion with mild heterogeneous enhancement. The lesion was excised and histologic examination was consistent with an inflammatory myofibroblastic tumor. No adjuvant therapy was needed and the patient remained asymptomatic with no evidence of tumor recurrence during the 2 years of follow-up.

Inflammatory myofibroblastic tumor of the bladder

We illustrate a case of an inflammatory myofibroblastic tumor (IMT) involving the bladder in a woman with dysuria and review the literature and differential diagnosis. Inflammatory myofibroblastic tumor, also referred to as pseudosarcomatous myofibroblastic proliferation, is a rare lesion that can arise in the genitourinary system and is characterized by a fascicular arrangement of myofibroblasts with admixed inflammatory cells and slitlike vessels. Urinary bladder IMT can be a diagnostic pitfall because its histologic features (brisk mitoses, invasion into muscularis propria, and prominent nucleoli) can mimic malignancy. The differential diagnosis of urinary bladder IMT includes sarcomatoid carcinoma and leiomyosarcoma. Diagnostic features such as bland nuclear chromatin, ganglion-like cells, pale eosinophilic cytoplasm with long processes, overexpression of anaplastic lymphoma kinase (immunohistochemistry or gene rearrangement studies), and the absence of atypical mitoses help distinguish IMT from its malignant mimics. Current controversies regarding postoperative spindle cell nodule and IMT are discussed.

Inflammatory myofibroblastic tumors of the urinary bladder: a systematic review

We systemically reviewed the literature on inflammatory myofibroblastic tumors (IMTs) of the urinary bladder and compared between anaplastic lymphoma kinase (ALK)-positive and ALK-negative IMTs. An extensive search of the literature was performed in Medline and Web of Science using the following terms: "inflammatory myofibrolastic tumor," "inflammatory pseudotumor," and "bladder." A manual search was also performed using the web-based search engine Google Scholar. Reference lists of the retrieved articles were reviewed for other relevant studies. Patients' and disease characteristics of each individual case were reviewed. Further analyses were performed to compare between ALK-positive and ALK-negative IMTs. Forty-one studies were identified, and 182 patients were included for review and subsequent analyses. Of the IMTs, 65% were ALK-positive. Local tumor recurrence rate was 4%, and no cases of distant metastases have been reported. Compared with ALK-negative IMTs, ALK-positive IMTs had a female predilection with a sex ratio (male:female) of 1:1.67 (P = .048). ALK-positive IMTs also appeared to occur in younger patients (P = .072). No significant differences were noted in terms of their clinical presentations and histologic features. On immunohistochemical staining, ALK-positive IMTs had more positive results for desmin (P = .042) and p53 (P = .05), and more negative results for clusterin (P = .003). In summary, ALK-positive IMTs of the urinary bladder had a female predilection, appeared to occur more frequently in younger patients, and had different immunohistochemical staining patterns when compared with ALK-negative IMTs. Regardless of its ALK status, IMT of the urinary bladder has a good prognosis after surgical resection.

Best practices recommendations in the application of immunohistochemistry in the bladder lesions: report from the International Society of Urologic Pathology consensus conference

The bladder working group of the 2013 International Society of Urologic Pathology (ISUP) Conference on Best Practices Recommendation in the Application of Immunohistochemistry (IHC) in Urologic Pathology discussed 5 settings in which IHC is commonly used in clinical practice. With regard to markers for urothelial differentiation, the committee found that there is no ideal marker or established panel to confirm urothelial differentiation. On the basis of the differential diagnostic consideration, positivity for GATA3, CK20, p63, and either high-molecular weight cytokeratin (HMWCK) or cytokeratin (CK)5/6 is of value in proving urothelial differentiation in the appropriate morphologic and clinical context. With regard to the role of IHC in the distinction of reactive atypia from urothelial carcinoma in situ, the committee recommended that morphology remains the gold standard in this differential diagnosis and that, at best, the IHC panel of CK20/p53/CD44(s) has potential utility but is variably used and has limitations. The immunostaining pattern must be interpreted with strict morphologic correlation, because overreliance on IHC may be misleading, particularly in the posttreatment setting. IHC has no role in the distinction of dysplasia versus carcinoma in situ and in the grading of papillary urothelial carcinoma. IHC may have a limited but distinct role in staging of bladder cancer. In a subset of cases, depending on the clinical and histologic context, broad-spectrum cytokeratins (to identify early or obscured invasion) and desmin (distinction of muscle from desmoplasia and to highlight muscle contours for subclassification) may be helpful. Limited experience and conflicting data preclude smoothelin or vimentin to be recommended routinely for subclassifying muscle type at this time. In the workup of a spindled cell proliferation of the bladder and in limited specimens, we recommend an immunohistochemical panel of 6 markers including ALK1, SMA, desmin, cytokeratin (AE1/AE3), and p63 with either of HMWCK or CK5/6. Currently, there are no prognostic immunohistochemical or molecular studies that are recommended to be routinely performed on biopsy or resection specimens.

Inflammatory Myofibroblastic Tumor: A Case Study

Inflammatory myofibroblastic tumor (IMT) is a rare benign lesion found in many locations throughout the body and genitourinary tract. Endoscopically and radiographically, these solid lesions cannot be distinguished from malignant bladder tumors. We present the case of a 21-year-old woman who presented with painful obstructive and irritative voiding symptoms of short duration. After extensive preoperative evaluation failed to reveal a definitive diagnosis, the patient underwent partial cystectomy. Final pathology revealed IMT. A high index of suspicion is required for diagnosis of IMT as it is often difficult to distinguish from its malignant counterparts.

Inflammatory myofibroblastic tumor of the urinary bladder with benign pelvic lymph node enlargement: a case report

Inflammatory myofibroblastic tumors (IMTs) rarely occur in the urinary bladder. It is apparently difficult to distinguish these tumors from other malignant spindle cell proliferations. Herein, we report a case of IMT of the urinary bladder with enlarged pelvic lymph nodes. The definitive pathological diagnosis could not be established by biopsy. Instead, the diagnosis of IMT of the urinary bladder was determined by a positive reaction to anaplastic lymphoma kinase by immunohistochemistry after radical cystectomy. No malignant findings were observed on histopathological evaluations of the enlarged lymph nodes.

Inflammatory Myofibroblastic Tumours of the Urinary Bladder: Multi-Centre 18-Year Experience

Objective: To review a series of inflammatory myofibroblastic tumours (IMTs) of the urinary bladder in 10 hospitals in Hong Kong. Methods: A database search in the pathology archives of 10 hospitals in Hong Kong from 1995 to 2013 was performed using the key words ‘inflammatory myofibroblastic tumour', ‘inflammatory pseudotumour' and ‘spindle cell lesion'. Patient characteristics, clinical features, histological features, immunohistochemical staining results and treatment outcomes were reviewed. Results: Nine cases of IMT of the urinary bladder were retrieved. The mean age was 45.4 ± 22.8 years (range 11-78). Eight patients (88.9%) presented with haematuria and 5 patients (55.6%) had anaemia with a mean haemoglobin level of 6.8 ± 1.3 g/dl. Histologically, the majority of patients (77.8%) had a compact spindle cell pattern. Anaplastic lymphoma kinase staining was positive in 75% of cases. During a mean follow-up period of 43.4 months (range 8-94), none of them developed any local recurrence or distant metastasis. Conclusions: A high index of suspicion of IMT should be maintained for young patients presenting with bleeding bladder tumours and significant anaemia. IMTs of the urinary bladder run a benign disease course, and good prognosis can be achieved after surgical resection.

Inflammatory myofibroblastic tumor of the thigh without bone involvement: a case report

Inflammatory myofibroblastic tumors are rare, and those located in the extremities without bone involvement are even rarer. We present the case of a 61-year-old Chinese male patient with an inflammatory myofibroblastic tumor of the right thigh. It was excised and a histopathologic examination revealed an inflammatory myofibroblastic tumor. This case is presented by virtue of its rare location.

Sarcomatoid variant of urothelial carcinoma (carcinosarcoma, spindle cell carcinoma): a review of the literature

Background. Sarcomatoid variant of urothelial carcinoma (SVUC) was added to the WHO classification in 2004. Aims. To review the literature. Materials and Method. Various internet databases were used. Result. SVUCs are rare biphasic malignant neoplasms exhibiting morphologic/immunohistochemical evidence of epithelial and mesenchymal differentiation with the presence or absence of heterologous elements. Some cases of SVUC have been associated with radiation therapy and cyclophosphamide treatment. Patients' ages range from 50 to 77 years (mean age 66). Patients tend to be younger and they more commonly presented with high-grade histology and advanced stage disease, in comparison with patients who had conventional urothelial carcinoma (CUC). Results of molecular/genetic studies strongly argue for a common monoclonal cell origin of both the epithelial and mesenchymal components in SUVC. The cancer specific survival of SVUC is poor in comparison with CUC. Radical surgical excision and chemoradiation may be associated with improved prognosis; chemoradiation as an organ preserving alternative to radical excision may be associated with improved outcome. There is no consensus opinion on the best treatment modalities for SUVC. Conclusions. SVUC is rare and is associated with inferior outcome compared with CUC. A multicentre trial of various treatment options is required. Cases of SVUC should be reported.

Low-grade myofibroblastic proliferations of the urinary bladder

CONTEXT

Myofibroblastic proliferations of the urinary bladder, which share some similarities with nodular fasciitis, were first reported in 1980. Since then, they have had several designations, the most frequently used being inflammatory myofibroblastic tumor. Based on both histopathologic and prognostic grounds, some authors prefer the term pseudosarcomatous myofibroblastic proliferation, at least for some of the proliferations. These same scientists also assimilate the so-called postoperative spindle cell nodules with the pseudosarcomatous myofibroblastic proliferations. Little is known about these low-grade myofibroblastic proliferations.

OBJECTIVES

To review the literature about low-grade myofibroblastic proliferations occurring in the urinary bladder.

DATA SOURCES

Textbooks and literature review. We obtained most of the clinicopathologic peculiarities from a patient population composed of the most-relevant, previously reported cases.

CONCLUSIONS

The low-grade myofibroblastic proliferations of the urinary bladder are rare lesions affecting males more often than they do females. The most-common signs and symptoms are hematuria and dysuria. Histopathologically, they are spindle cell proliferations in a loose myxoid stroma, even though compact proliferations or hypocellular fibrous patterns can be found. Immunohistochemistry is quite nonspecific, except for ALK-1 positivity (20%-89%). Fluorescence in situ hybridization has demonstrated clonal genetic aberrations involving the ALK gene in 50% to 60% of cases. After surgery, only 6% of patients experience local recurrence, without metastases or deaths from the disease. Malignant transformation has been reported exceptionally. These myofibroblastic proliferations are probably part of a continuum with, at one end, benign pseudosarcomatous proliferations and, at the opposite end, more-aggressive lesions. Because of the frequently indolent clinical course, aggressive treatment would be unjustified.

Mesenchymal tumours of the bladder and prostate: an update

Mesenchymal tumours of the urinary bladder and prostate are infrequent neoplasms. The body of literature is growing with isolated case reports and short series, and the majority of cases are benign neoplasms. Other than stromal tumour of uncertain malignant potential and prostatic stromal sarcoma, both neoplasms derived from the specific prostatic stroma, the mesenchymal neoplasms in these locations are identical to their counterparts seen in other organs. However, the limited amount of tissue generated by biopsy and rarity of mesenchymal lesions in these sites create unique diagnostic difficulties, while correct classification of the neoplasm often bears significant impact on prognosis and therapeutic strategy. In this review we summarise the diagnostic features, focus on the differential diagnosis, and highlight the potential diagnostic pitfalls of mesenchymal tumours of the bladder and prostate.

Colonic inflammatory myofibroblastic tumours: an institutional review

AIM

The aim of the study was to present the largest series of colonic inflammatory myofibroblastic tumour (C-IMFT) in the literature so far and to provide a review of this condition.

METHOD

A retrospective review was carried out of a consecutive series of patients diagnosed with a C-IMFT at a community-based hospital with a specialized gastrointestinal unit between 2002 and 2011. The main outcome measures were success rate and postoperative complications. Using a set of terms we searched the PubMed database for papers published on C-IMFT. We reviewed the data from these studies and case reports.

RESULTS

There were seven patients with a histopathologically proven C-IMFT. The patients' mean age was 39 ± 11.3 years. Four presented with clinical features of intestinal obstruction of varying severity and three with symptoms of anaemia. Complete surgical resection with end-to-end anastomosis was performed. The gross morphology included polypoidal myxoid tumours that served as a lead point for intussusception in two cases, a whorled mass in two and a circumferential infiltrative tumour in three. Microscopically, all tumours had typical features of IMFT with a variable expression of anaplastic lymphoma kinase (ALK-1) and tumour-free resection margins. All patients were well without local recurrence or metastasis at a mean follow-up of 46.8 ± 11.9 months.

CONCLUSION

Surgical resection is effective for this rare tumour which mostly behaves in a benign manner. Our review supports the need for patients to be followed up for long periods because of the possibility of metastasis or late recurrence.

Anaplastic lymphoma kinase as a therapeutic target

INTRODUCTION

Anaplastic lymphoma kinase (ALK), a tyrosine kinase receptor, has been initially identified through its involvement in chromosomal translocations associated with anaplastic large cell lymphoma. However, recent evidence that aberrant ALK activity is also involved in an expanding number of tumor types, such as other lymphomas, inflammatory myofibroblastic tumor, neuroblastomas and some carcinomas, including non-small cell lung carcinomas, is boosting research progress in ALK-targeted therapies.

AREAS COVERED

The first aim of this review is to describe current understandings about the ALK tyrosine kinase and its implication in the oncogenesis of human cancers as a fusion protein or through mutations. The second goal is to discuss its interest as a therapeutic target and to provide a review of the literature regarding ALK inhibitors. Mechanisms of acquired resistance are also reviewed.

EXPERT OPINION

Several ALK inhibitors have recently been developed, offering new treatment options in tumors driven by abnormal ALK signaling. However, as observed with other tyrosine kinase inhibitors, resistance has emerged in patients treated with these agents. The complexity of mechanisms of acquired resistance recently described suggests that other therapeutic options, including combination of ALK and other kinases targeted drugs, will be required in the future.

Variants and unusual patterns of prostate cancer: clinicopathologic and differential diagnostic considerations

Beyond the typical acinar morphology observed in the majority of prostatic adenocarcinomas, a spectrum of morphologic variants and prostate cancer subtypes exists. These unusual entities may be classified as: (1) cancer morphologies arising by divergent differentiation of prostatic ductal, acinar, or basal cells and associated with unique clinical features and/or therapeutic approaches, and (2) histologies occurring in the context of usual prostatic adenocarcinoma that may result in diagnostic misinterpretation or difficulties in Gleason grade assignment, especially in limited samples. This article details a number of variants, with emphasis on diagnostic criteria, differential diagnoses, and clinical significance.

Multiple inflammatory myofibroblastic tumor of the duodenum: case report and literature review

INTRODUCTION

Inflammatory myofibroblastic tumor (IMT) is a rare low-grade malignant mesenchymal tumor, which can occur at any location, although the lung is the most commonly affected organ. It is extremely rare in the duodenum and only two cases have been reported previously. We report, to our knowledge, the first case of multiple neoplastic lesions.

CASE REPORT

A 20-year-old male presented with the chief complaints of intermittent right epigastric pain, nausea and vomiting. Imaging examination, electronic gastroscopy and preoperative biopsy revealed undefined lesions in the duodenum. Pancreaticoduodenectomy was performed and diagnosis of multiple IMT was confirmed by pathological biopsy of the excised tumor. A satisfactory outcome was proved by the follow-up 1 year after curative operation.

CONCLUSION

IMT can be diagnosed by histological examination and immunohistochemical test after surgical resection. Patients can benefit from radical resection with favorable prognosis.

Fibroblastic and myofibroblastic tumors in children and adolescents

Fibroblastic and myofibroblastic tumors in children and adolescents are a relatively common group of soft tissue proliferations that range from reactive to hamartomatous to neoplastic, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic and immunohistochemical overlap, despite significant clinical, genetic, and prognostic differences. The fibromatoses are a major subgroup, and all types of fibromatoses can occur in the 1st 2 decades of life. Intermediate and malignant fibroblastic-myofibroblastic tumors are an important group that includes variants of fibrosarcoma and other tumors with recurrent cytogenetic or molecular genetic abnormalities and low metastatic potential. Pathologic examination is enhanced by adjunct techniques, such as immunohistochemistry, cytogenetics, and molecular genetics, although morphology provides the ultimate criteria for a specific diagnosis. This article reviews the clinicopathologic features of fibroblastic and myofibroblastic tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents, the use of diagnostic adjuncts, and differential diagnoses.

ALK-1 Protein Expression and ALK Gene Rearrangements Aid in the Diagnosis of Inflammatory Myofibroblastic Tumors of the Female Genital Tract

Context.—Inflammatory myofibroblastic tumor is a predominantly benign, spindle cell, mesenchymal neoplasm with myxoid areas that occurs rarely in the female genital tract and may be confused with other spindle cell lesions, particularly leiomyosarcoma.

Objective.—To investigate the utility of detecting anaplastic lymphoma kinase-1 protein expression and ALK gene rearrangements in the diagnosis of inflammatory myofibroblastic tumors in the female genital tract.

Design.—Eight inflammatory myofibroblastic tumors arising in the female genital tract and seen in consultation (from 2004 to 2011) were reviewed. Immunohistochemistry for anaplastic lymphoma kinase-1 and fluorescence in-situ hybridization studies for ALK gene rearrangements were performed.

Results.—The anatomic sites included myometrium (4 cases) and endometrium, fallopian tube, cervix, and a cervical polyp (1 each), with a patient age range from 25 to 52 years. Histologic features ranged from bland spindle cells to striking cytologic atypia, embedded in a prominent myxoid background. Anaplastic lymphoma kinase-1 immunohistochemistry was positive in 7 cases. Fluorescence in-situ hybridization studies detected ALK gene rearrangements in 5 cases. Five cases had both immunopositivity and fluorescence in-situ hybridization abnormalities, 2 cases had immunopositivity only, and 1 case was negative by both methods.

Conclusions.—This is the first report, to our knowledge, of ALK gene rearrangements in inflammatory myofibroblastic tumors in the female genital tract. If a myxoid background is appreciated in a spindle cell lesion of the female genital tract, especially if inflammatory cells are present, anaplastic lymphoma kinase-1 staining along with fluorescence in situ hybridization studies, for ALK gene rearrangements, may aid in distinguishing inflammatory myofibroblastic tumors from their malignant mimics.

Differential diagnosis of inflammatory myofibroblastic tumour and low-grade myofibroblastic sarcoma: two case reports with a literature review

Inflammatory myofibroblastic tumour (IMT) and low-grade myofibroblastic sarcoma (LGMS) have similar morpho logical and immunophenotypic features, but LGMS is more malignant than IMT and the treatment requires a wider surgical margin plus post-operative chemotherapy or radiotherapy. To date, only 28 cases of IMT and two cases of LGMS have been reported in the laryngopharynx. Recent studies have suggested that anaplastic lymphoma kinase (ALK) and cytokeratin are important markers for differentiating between the two tumours. Here, two cases involving different myofibroblastic tumours of the larynx are reported. Based on the histological and immunohistochemical results, case 1 was diagnosed as IMT involving the right arytenoepiglottic fold, while case 2 was diagnosed as LGMS involving the epiglottic-glossal surface. There was no recurrence or metastasis in either case after post-operative follow-up (12 and 14 months, respectively). It is difficult to distinguish IMT from LGMS; both morphological and immunohistological analyses are required.

Post-traumatic inflammatory pseudotumor of the breast with atypical morphological features: A potential diagnostic pitfall. Report of a case and a critical review of the literature

Although inflammatory pseudotumor (IPT) and inflammatory myofibroblastic tumor (IMT) may share a common morphology, they are distinct clinico-pathologic entities. Unfortunately, the terms IMT and IPT are still used interchangeably, especially when lesions occur in unusual sites, including breast. All the cases of IMT/IPT involving the breast have raised spontaneously without any apparent prior injury. We herein report the first case of a post-traumatic IPT of the breast parenchyma in a 22-year-old male. Histologically, the lesion was highly cellular and composed of spindle cells arranged in a predominant fascicular pattern. Notably, mono- or multi-nucleated large pleomorphic cells were observed. Inflammatory cells, especially plasma cells and lymphocytes, were closely admixed with the spindle cell proliferation. The overall picture was reminiscent of an "IMT with atypical features", typically seen in lung, abdomen, pelvis, and retroperitoneum of children. Immunohistochemically, the spindle-shaped and large pleomorphic cells were immunoreactive to vimentin, α-smooth muscle actin, and desmin. No immunoreactivity was obtained with ALK-1 protein. The present case contributes to widening the morphological spectrum of IPT of the breast, emphasizing the possibility that a reactive lesion may contain large pleomorphic cells that may represent a potential diagnostic pitfall. Lastly, we suggest that the diagnosis of IMT of the breast should be rendered with caution when dealing with ALK-negative spindle cell lesions in adult patients, and alternative diagnoses, including IPT, should be seriously considered.