A case of an inflammatory myofibroblastic tumor in the lung which expressed TPM3-ALK gene fusion

Reprint of: Unusual non-neoplastic lesions of the lung

Many nonneoplastic conditions that may affect the lung are in reality rare or unusual manifestations of metabolic processes, inflammatory conditions, or unknown etiology. Because of their rarity, they can often be confused with malignant neoplasms. Familiarity with these conditions not only will expedite further treatment for these patients but also will avoid the process of more tests or unnecessary surgical procedures. The nomenclature for some of those conditions is still controversial. The clinical outcome of these conditions can be quite variable, with some patients surviving a long number of years and others eventually succumbing to the disease. We will limit our discussion in this review to four of these conditions, including inflammatory pseudotumor (inflammatory myofibroblastic tumor), placental transmogrification of lung, alveolar microlithiasis, and metastatic calcification. Although these lesions are not part of the gamut of neoplastic conditions affecting the lung, they are nonetheless important to recognize, as their outcome may not necessarily be an innocuous one.

Inflammatory myofibroblastic tumor of the uterus: a clinicopathological, immunohistochemical, and molecular analysis of 13 cases highlighting their broad morphologic spectrum

Inflammatory myofibroblastic tumors of the uterus are rare, and although most have a favorable prognosis, a small subset exhibit extrauterine disease, recur, or cause death. In this study, we evaluated the morphology and immunoprofile of 13 uterine inflammatory myofibroblastic tumors, including four with aggressive behavior. ALK rearrangements were detected by fluorescence in situ hybridization and fusion partners by anchored multiplex assay. Patients ranged from 8 to 63 (mean 39) years and tumors from 2.5 to 20 (mean 7.4) cm. Myxoid, compact, and hyalinized patterns were noted in 13, 12, and 2 tumors, ranging from 1 to 100%, 5 to 99%, and 0 to 5%, respectively. Nuclear atypia was mild in six (46%), moderate in five (38%), and severe in two (15%), with ganglion-like cells in two tumors. Mitoses ranged from 0 to 24 (mean 5) per 10 high-power fields. Inflammation was mild in five (38%), moderate in three (23%), and marked in five (38%), consisting of a lymphoplasmacytic infiltrate that was lymphocyte-predominant in six (46%). Lymphovascular invasion was noted in two (15%) and necrosis in eight (62%). All but one tumor were ALK-positive by immunohistochemistry, with granular cytoplasmic staining in nine (82%). ALK rearrangements (tested in 10) were detected in eight and was absent in one. The remaining tumor showed an isolated green 5' ALK signal. Fusion partners were identified in 10 (77%) and included THBS1 (n=3), IGFBP5 (n=2), DES (n=2), SEC31 (n=1), TPM3 (n=1), and TIMP3 (n=1). Size ≥8 cm was predictive of aggressive behavior (P<0.01), with increased mitoses (≥7 per 10 high-power fields), lymphovascular invasion, and compact-predominance approaching statistical significance. These data show that inflammatory myofibroblastic tumors of the uterus are morphologically heterogenous with frequent ALK expression and a variety of ALK fusion partners. Recognition of this rare mesenchymal neoplasm is crucial as those with aggressive behavior can potentially be treated with tyrosine kinase inhibitors.

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.

Anaplastic lymphoma kinase protein expression predicts micrometastases and prognosis for patients with hepatocellular carcinoma

The present study aimed to investigate anaplastic lymphoma kinase (ALK) status in hepatocellular carcinoma (HCC) and to evaluate whether abnormalities in expression were associated with patient prognosis. ALK status was investigated using immunohistochemistry (IHC), reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and fluorescence in situ hybridization (FISH) assays in 342 HCC patients. In addition, rapid amplification of complementary DNA ends-coupled PCR sequencing was performed, in order to confirm the presence of ALK abnormalities in patients exhibiting ALK messenger RNA (mRNA) overexpression. The correlation between ALK expression and the clinicopathological features and prognosis of the HCC patients was statistically analyzed. The results of the present study revealed overexpression of ALK protein and mRNA; furthermore, ALK gene copy number gains were observed via IHC (44.7%; 153/342), RT-qPCR (47.4%; 162/342) and FISH (32.7%; 112/342) analyses, although ALK rearrangement or mutation was not demonstrated in the results of any of these assays. ALK protein expression levels were significantly associated with hepatitis C virus (HCV) status (P<0.001) and the presence of micrometastases (P=0.011). Within the entire patient cohort, ALK expression was associated with poor progression-free survival (PFS; P=0.041). Subsequent analysis in patient subgroups that demonstrated hepatitis B surface antigen positivity, HCV negativity, stage III-IV disease, recurrence and micrometastasis positivity revealed that overall survival (OS) and PFS were significantly reduced in those patients exhibiting ALK expression compared with those patients who were negative for ALK expression. Multivariate analysis revealed that ALK expression was an independent risk factor for OS (P=0.042) and PFS (P=0.033), particularly for patients with stage III-IV tumors. Thus, ALK may serve as a novel indicator for the metastatic behavior and prognosis of HCC.

Pulmonary inflammatory myofibroblastic tumor harboring EML4-ALK fusion gene

Inflammatory myofibroblastic tumor is a rare tumor deriving from mesenchymal tissue. Approximately 50% of inflammatory myofibroblastic tumors harbor an anaplastic lymphoma kinase fusion gene. Pulmonary inflammatory myofibroblastic tumors harboring tropomyosin3-anaplastic lymphoma kinase or protein tyrosine phosphatase receptor-type F polypeptide-interacting protein-binding protein 1-anaplastic lymphoma kinase have been reported previously. However, it has not been reported that inflammatory myofibroblastic tumors harbor echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion gene which is considered to be very specific to lung cancers. A few tumors harboring echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion gene other than lung cancers have been reported and the tumors were all carcinomas. A 67-year-old man had been followed up for a benign tumor for approximately 3 years before the tumor demonstrated malignant transformation. Lobectomy and autopsy revealed that an inflammatory myofibroblastic tumor harboring echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion gene had transformed into an undifferentiated sarcoma. This case suggests that echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion is an oncogenic event in not only carcinomas but also sarcomas originating from stromal cells.

Multifocal intrathoracic inflammatory myofibroblastic tumour in children

Pulmonary inflammatory myofibroblastic tumour is the most common benign pulmonary tumour in childhood; however it is seldom diagnosed radiologically. We report three cases of biopsy-proven inflammatory myofibroblastic tumour that presented as large aggressive intrathoracic masses mimicking a malignant process. Two cases also had multifocal areas of origin. The possibility of inflammatory myofibroblastic tumour should be considered in a child presenting with a large aggressive pleuropulmonary mass lesion even with multifocal origin.

Fusion of EML4 and ALK is associated with development of lung adenocarcinomas lacking EGFR and KRAS mutations and is correlated with ALK expression

Background

The anaplastic lymphoma kinase (ALK) gene is frequently involved in translocations that lead to gene fusions in a variety of human malignancies, including lymphoma and lung cancer. Fusion partners of ALK include NPM, EML4, TPM3, ATIC, TFG, CARS, and CLTC. Characterization of ALK fusion patterns and their resulting clinicopathological profiles could be of great benefit in better understanding the biology of lung cancer.

Results

RACE-coupled PCR sequencing was used to assess ALK fusions in a cohort of 103 non-small cell lung carcinoma (NSCLC) patients. Within this cohort, the EML4-ALK fusion gene was identified in 12 tumors (11.6%). Further analysis revealed that EML4-ALK was present at a frequency of 16.13% (10/62) in patients with adenocarcinomas, 19.23% (10/52) in never-smokers, and 42.80% (9/21) in patients with adenocarcinomas lacking EGFR and KRAS mutations. The EML4-ALK fusion was associated with non-smokers (P = 0.03), younger age of onset (P = 0.03), and adenocarcinomas without EGFR/KRAS mutations (P = 0.04). A trend towards improved survival was observed for patients with the EML4-ALK fusion, although it was not statistically significant (P = 0.20). Concurrent deletion in EGFR exon 19 and fusion of EML4-ALK was identified for the first time in a Chinese female patient with an adenocarcinoma. Analysis of ALK expression revealed that ALK mRNA levels were higher in tumors positive for the EML-ALK fusion than in negative tumors (normalized intensity of 21.99 vs. 0.45, respectively; P = 0.0018). However, expression of EML4 did not differ between the groups.

Conclusions

The EML4-ALK fusion gene was present at a high frequency in Chinese NSCLC patients, particularly in those with adenocarcinomas lacking EGFR/KRAS mutations. The EML4-ALK fusion appears to be tightly associated with ALK mRNA expression levels. RACE-coupled PCR sequencing is a highly sensitive method that could be used clinically for the identification of EML4-ALK-positive patients.

Anaplastic lymphoma kinase expression and prognosis in inflammatory myofibroblastic tumours of the maxillary sinus

Inflammatory myofibroblastic tumours (IMT) of the nasal cavity and nasal sinus are rare and, although over 50 cases have been reported in the English-language literature, their precise aetiology and biological behaviour have not been elucidated. Recent studies suggest that anaplastic lymphoma kinase (ALK)-positive tumours have a very low risk of metastasis, but ALK reactivity does not appear to correlate with recurrence. Between March 2002 and December 2008, we encountered three cases of maxillary sinus IMT and investigated them to determine the clinicopathological course, prognosis and immunohistochemical expression of ALK. Two of the patients died < 13 months after the initial diagnosis and the third had multiple recurrences. All three cases were immunohisto chemically negative for ALK expression. IMT of the sino-nasal tract is rare and may undergo malignant transformation in a minority of cases. The three cases manifested progressive extension with bone destruction and multiple recurrences, and two cases had a fatal outcome and one case had high recurrence.

Benign Tumors and Tumorlike Conditions of the Lung

Context.—Benign tumors and tumorlike conditions of the lung are encountered in the pathologic evaluation of asymptomatic and symptomatic lung nodules. Since many of these lesions are uncommon, they can be diagnostically challenging.

Objective.—To review the current classification of benign lung tumors, with emphasis on histopathology and useful ancillary studies.

Data Sources.—The current World Health Organization classification system for lung neoplasms and review of relevant publications.

Conclusions.—Despite improved imaging techniques, benign lung nodules are encountered in wedge biopsy and resection specimens. Histopathology, immunohistochemistry, and molecular techniques ensure accurate pathologic diagnosis and have shed light on the histogenesis of these unusual lesions.

Unusual non-neoplastic lesions of the lung

Many nonneoplastic conditions that may affect the lung are in reality rare or unusual manifestations of metabolic processes, inflammatory conditions, or unknown etiology. Because of their rarity, they can often be confused with malignant neoplasms. Familiarity with these conditions not only will expedite further treatment for these patients but also will avoid the process of more tests or unnecessary surgical procedures. The nomenclature for some of those conditions is still controversial. The clinical outcome of these conditions can be quite variable, with some patients surviving a long number of years and others eventually succumbing to the disease. We will limit our discussion in this review to four of these conditions, including inflammatory pseudotumor (inflammatory myofibroblastic tumor), placental transmogrification of lung, alveolar microlithiasis, and metastatic calcification. Although these lesions are not part of the gamut of neoplastic conditions affecting the lung, they are nonetheless important to recognize, as their outcome may not necessarily be an innocuous one.