Hala R. Makhlouf

Gastrointestinal Stromal Tumors, Intramural Leiomyomas, and Leiomyosarcomas in the Duodenum A Clinicopathologic, Immunohistochemical, and Molecular Genetic Study of 167 Cases

&NA; In this study we analyzed the clinicopathologic features of duodenal smooth muscle or stromal tumors, including 156 GISTs, 6 leiomyomas (LMs), and 5 leiomyosarcomas (LMSs) from the files of the Armed Forces Institute of Pathology and the Haartman Institute of the University of Helsinki. GISTs were documented as KIT positive (n = 109); 47 tumors were also included because of their histologic identity to KIT‐positive cases. GIST‐specific c‐kit gene mutations were documented in exon 11 in 9 of 30 cases (30%) and exon 9 in 4 of 30 cases (13%). The GISTs occurred in patients with an age range of 10–88 years (median 56 years); 54% were male. Ten patients had neurofibromatosis type I; six of them had multiple GISTs. The GISTs ranged from small asymptomatic intramural or external nodules to large masses that extended into the retroperitoneum (median size 4.5 cm). They were mostly spindle cell tumors; three malignant GISTs had an epithelioid morphology, and 81 cases had skeinoid fibers. The tumors often coexpressed CD34 and KIT (54%) and were variably positive for smooth muscle actin (39%) and S‐100 protein (20%) but never for desmin. A total of 86% of patients with tumors >5 cm with >5 mitoses/50 high power fields (HPF) (n = 21) died of disease, whereas no tumor <2 cm with <5 mitoses/50 HPF (n = 12) recurred or caused death. Long latency was common between primary operation and recurrences or metastases; either one occurred in 49 of 140 patients with follow‐up (35%). No formula could accurately predict metastases, which occasionally developed even if mitotic activity was <5/50 HPF and size <5 cm. Metastases were in the abdominal cavity, liver, and rarely in bones and lungs but never in lymph nodes. Four actin‐ and desmin‐positive and KIT‐negative benign intramural LMs were similar to those more often seen in the esophagus. There were five LMSs, one of which formed a polypoid intraluminal mass; all were actin positive and KIT negative. The great majority of duodenal mesenchymal tumors are GISTs, which have a spectrum from small indolent tumors to overt sarcomas. LMs and LMSs are rare.Gastrointestinal stromal tumors (GISTs), the specific KITpositive mesenchymal tumors of the gastrointestinal tract, have been sporadically reported in the rectum, but there are few clinicopathologic series. In this study we analyzed the clinicopathologic features of 133 anorectal GISTs, 3 intramural leiomyomas (LMs), and 8 leiomyosarcomas (LMSs) from the files of the Armed Forces Institute of Pathology and the Haartman Institute of the University of Helsinki. Ninety-six GISTs were documented as KIT-positive and three additional ones as CD34-positive. Thirty-four tumors were included by their histologic similarity to KITor CD34-positive cases. GISTspecific c-kit gene mutations, mostly in exon 11, were documented in 18 of 29 cases (62%). The GISTs occurred in adults with the age range of 17–90 years (median 60 years) with a significant male predominance (71%). The tumors ranged from small asymptomatic intramural nodules to large masses that bulged into pelvis causing pain, rectal bleeding, or obstruction. They were mostly highly cellular spindle cell tumors; four tumors had an epithelioid morphology. The tumors coexpressed CD34 and KIT and were rarely positive for smooth muscle actin or desmin and never for S-100 protein. Seventy percent of patients with tumors >5 cm with more than 5 mitoses/50 high power fields (HPF) (n 31) died of disease, whereas only one tumor <2 cm with <5 mitoses/50 HPF (n 21) recurred and none caused death. Long latency was common between primary operation and recurrences and metastases; either one occurred in 60 of 111 patients with follow-up (54%). Distant metastases were in the liver, bones, and lungs. Three benign actinand desmin-positive and KIT-negative intramural LMs, similar to those seen in the esophagus, were identified. There were eight LMSs, six of which formed a polypoid intraluminal mass and were actin-positive and KIT-negative. Despite high mitotic counts, only one LMS patient died of disease. A great majority of rectal smooth muscle and stromal tumors are GISTs, which have a spectrum from minimal indolent tumors to overt sarcomas. Intramural LMs are exceptional, and true LMSs are rare, and similar to colonic ones, often present as intraluminal polypoid masses that appear to have a better prognosis than GISTs with similar mitotic rates.

Gastrointestinal stromal tumors of the jejunum and ileum: a clinicopathologic, immunohistochemical, and molecular genetic study of 906 cases before imatinib with long-term follow-up.

Gastrointestinal (GI) stromal tumors (GISTs), the specific KIT- or PDFGRA-signaling driven mesenchymal tumors, are the most common mesenchymal tumors of the GI tract. This study analyzed 1091 tumors originally classified as smooth muscle tumors of the small intestine (including jejunum or ileum and excluding duodenum), and found that 906 (83%) of these were GISTs. The GIST patients had 55:45 male-to-female ratio with a median age of 59 years (range, 13–94 years). Only 0.6% of tumors occurred before the age of 21 years and 13.6% before the age of 40 years. The tumors varied from 0.3 to 40 cm (median, 7.0 cm) and most commonly presented with GI bleeding or acute abdomen; 18% were incidentally detected. Histologically, the tumors were relatively monotypic with spindle cell (86%), epithelioid (5%), or mixed patterns (9%). Skeinoid fibers were present in 44% of cases, and their presence was associated with a favorable course. Most epithelioid tumors were malignant, and this morphology sometimes emerged from less cellular and less mitotically active spindle cell tumors, suggesting that it represented a transformation. KIT was immunohistochemically detected in 98%, CD34 in 40%, smooth muscle actin in 34%, desmin in 0.2%, and S-100 protein in 14% of the tumors tested. Outcome was strongly dependent on tumor size and mitotic activity, with an overall 39% tumor-related mortality, twice that for gastric GISTs. Only <3% of tumors <5 cm and ≤5 mitoses/50 HPF metastasized, whereas 86% of tumors >10 cm and >5 mitoses/50 HPF metastasized. In stark contrast to corresponding gastric tumors, tumors >10 cm with mitotic activity ≤5/50 HPF and those ≤5 cm with mitoses >5/50 HPF had a high metastatic rate (>50%); tumors >5 cm ≤10 cm with low mitotic rate had a 24% metastatic rate. The median survival times of patients with low mitotic rate tumors who died of disease decreased by increasing tumor size. KIT exon 11 mutations were detected in 90 cases, exon 9 mutation in 17 cases, and exon 17 mutation in 1 case; the presence of mutation or mutation type was not prognostically significant. There were no PDGFRA exon 12 or 8 mutations. Systematic data on prognosis of small intestinal GISTs of various size and mitotic activity categories can be helpful in management and surveillance of patients with these tumors.

Epithelioid hemangioendothelioma of the liver

Epithelioid hemangioendothelioma (EHE) is a rare neoplasm of vascular origin that occurs in the liver and other organs; its etiology is unknown.

Pathologic criteria for nonalcoholic steatohepatitis: Interprotocol agreement and ability to predict liver‐related mortality

Since the initial description of nonalcoholic steatohepatitis (NASH), several sets of pathologic criteria for its diagnosis have been proposed. However, their interprotocol agreement and ability to predict long‐term liver‐related mortality (LRM) have not been demonstrated. In this study, we examined patients with biopsy‐proven nonalcoholic fatty liver disease (NAFLD) for whom liver biopsy slides and clinical and mortality data were available. Liver biopsy samples were evaluated for a number of pathologic features and were classified according to the presence or absence of NASH by (1) the original criteria for NAFLD subtypes, (2) the nonalcoholic fatty liver disease activity score (NAS), (3) the Brunt criteria, and (4) the current studys criteria. All NASH diagnostic criteria and individual pathologic features were tested for agreement and for their independent associations with LRM, which were determined with a Cox proportional hazards model. Two hundred fifty‐seven NAFLD patients with complete data were included. The diagnoses of NASH by the original NAFLD subtypes and by the current studys definition of NASH were in almost perfect agreement (κ = 0.896). However, their agreement was moderate with NAS (κ = 0.470 and κ = 0.511, respectively) and only fair to moderate with the Brunt criteria (κ = 0.365 and κ = 0.441, respectively). Furthermore, the agreement of the Brunt criteria with NAS was relatively poor (κ = 0.178). During the follow‐up (median = 146 months), 31% of the patients died (9% were LRM). After we controlled for confounders, a diagnosis of NASH by the original criteria for NAFLD subtypes [adjusted hazard ratio = 9.94 (95% confidence interval = 1.28‐77.08)] demonstrated the best independent association with LRM. Among the individual pathologic features, advanced fibrosis showed the best independent association with LRM [adjusted hazard ratio = 5.68 (95% confidence interval = 1.50‐21.45)]. Conclusion: The original criteria for NAFLD subtypes and the current studys criteria for NASH were in almost perfect agreement, but their level of agreement with the NAS and Brunt criteria was lower. A diagnosis of NASH by the original criteria for NAFLD subtypes demonstrated the best predictability for LRM in NAFLD patients. (HEPATOLOGY 2011;)

Pathology of chronic hepatitis C in children: Liver biopsy findings in the Peds‐C Trial

There is relatively little information in the literature on the histopathology of chronic hepatitis C in children. The Peds‐C Trial, designed to test the efficacy and safety of peginterferon alfa‐2a and ribavirin in children, provided an opportunity to examine liver biopsies from 121 treatment‐naïve children, ages 2 to 16 (mean, 9.8 years) infected with the hepatitis C virus (HCV) and with no other identifiable cause for liver disease, signs of hepatic decompensation, or another significant nonhepatic disease. Liver biopsies were scored for inflammation, fibrosis, steatosis, and other histological features. Inflammation in the biopsy was minimal in 42%, mild in 17%, moderate in 38%, and severe in only 3%. Five had bridging fibrosis, and 2 had cirrhosis. Steatosis was absent in 56%, minimal in 34%, and mild in 10%. Inflammation scores correlated with fibrosis scores, serum alanine aminotransferase levels, and duration of infection, but not with age, body mass index z score, or HCV genotype. Fibrosis scores correlated with inflammation but not with age, HCV genotype, body mass index z score, or steatosis parameters. Steatosis correlated with serum alanine aminotransferase levels and body mass index z scores; overweight children had more fibrosis than the non‐overweight. In conclusion, in this cohort of HCV‐infected children, inflammation, fibrosis, and steatosis were milder than reported for treatment‐naïve adults with chronic hepatitis C, but there were several with bridging fibrosis or cirrhosis. The positive correlation of inflammation with duration of infection and fibrosis and of obesity with fibrosis suggest that children with chronic hepatitis C will be at risk for progressive liver disease as they age and possibly acquire other comorbid risk factors. (HEPATOLOGY 2007.)

Expression of KIT (CD117) in angiomyolipoma

Angiomyolipoma is a unique mesenchymal tumor postulated to arise from perivascular epithelioid cells. Immunohistochemical studies have shown that angiomyolipomas express the melanocytic markers HMB-45, MART-1 (Melan A), microphthalmia transcription factor, and tyrosinase, in addition to smooth muscle actin. KIT (CD117) is a transmembrane growth factor receptor expressed in cells of melanocytic and a variety of other cell lineages. To date, KIT immunoreactivity has not been systematically studied in angiomyolipoma. In this study we immunohistochemically analyzed a series of 21 angiomyolipomas (15 hepatic, six renal) with KIT. All were KIT positive: 14 of 21 (67%) with 3+ staining (>50% of tumor cells), 4 of 21 (19%) with 2+ staining (25–50% of tumor cells), and 3 of 21 (14%) with 1+ staining (<25% of tumor cells). In comparison, the percent of angiomyolipomas showing 3+ staining with HMB-45 was 62% and with Melan A was 52%. Positive KIT staining was detected in the epithelioid, spindle, and intermediate small round cells. Most cases showed diffuse cytoplasmic positivity. Strong perinuclear staining was present in the vacuolated clear epithelioid cells. There was focal KIT staining of fat cells. KIT was not detected in the endothelial cells lining blood vessels within the tumor. KIT may be a useful ancillary marker for the diagnosis of angiomyolipoma. Angiomyolipoma should be included in the differential diagnosis of KIT-positive tumors.

Carcinoma in Jejunal Pancreatic Heterotopia

BACKGROUND Although heterotopic pancreas in the gastrointestinal tract is not uncommon, jejunal pancreatic heterotopia is a rare finding, and malignant transformation in such a location is very unusual. METHODS We encountered a case of jejunal carcinoma in pancreatic heterotopia and because of its rarity, we reviewed the Armed Forces Institute of Pathology experience as well as the literature. The clinical, histopathologic, and immunohistochemical features were studied. RESULTS In 109 patients diagnosed as having pancreatic heterotopia in the gastrointestinal tract between 1970 and 1997 at the Armed Forces Institute of Pathology, 67 cases (62%) occurred in the stomach, 42 (38%) in the small intestine, and none in the large intestine. We found 2 patients with adenocarcinoma arising in pancreatic heterotopia. The 2 cases arose in the jejunum. One was of the ductal type, while the other was an acinar cell carcinoma with focal ductular differentiation. In both cases the nontumoral pancreatic tissue contained ducts, acini, and islets. Review of the literature yielded 26 reports of 28 cases of carcinoma arising in heterotopic pancreas; of these, 18 were well documented. Only 1 occurred in the jejunum, and none was of the acinar type. CONCLUSIONS Carcinoma in pancreatic heterotopia is rare, and acinar cell carcinoma in pancreatic heterotopia is extremely rare. Recognition of carcinoma in pancreatic heterotopia is important to prevent its misinterpretation as a metastatic tumor.

Carcinoid tumors of the ampulla of Vater

Although ampullary carcinoid tumors (ACs) are often categorized clinically as duodenal carcinoid tumors (DCs), there are distinct clinical and pathologic differences.

Melanoma markers in angiomyolipoma of the liver and kidney: a comparative study.

CONTEXT Melanoma markers, especially the new microphthalmia transcription factor (mitf), have not been previously compared in hepatic and renal angiomyolipomas. OBJECTIVES To evaluate expression of the novel melanocytic markers mitf and tyrosinase in angiomyolipomas, and to compare these markers with the established markers HMB-45 and melan-A in both hepatic and renal tumors. DESIGN Clinical, histopathologic, and immunohistochemical features of 15 hepatic angiomyolipomas were compared with those of 10 renal angiomyolipomas. RESULTS No significant differences between patients with hepatic angiomyolipomas and renal angiomyolipomas were found with respect to age, gender, race, and tumor size. Hepatic angiomyolipomas exhibited a predominance of the epithelioid smooth muscle cell component, in contrast to their renal counterparts, which were predominantly spindled. The smooth muscle cells expressed HMB-45 in 100% of cases in both groups, melan-A in 14 of 15 hepatic angiomyolipomas and 8 of 9 renal angiomyolipomas, mitf in 5 of 12 hepatic angiomyolipomas versus 6 of 10 renal angiomyolipomas, and tyrosinase in 3 of 12 and 2 of 10 hepatic angiomyolipomas and renal angiomyolipomas, respectively. The extent and intensity of immunostaining with HMB-45 and melan-A were dependent on whether spindled or epithelioid cells predominated; the epithelioid cells showed stronger and more widespread reactivity than the spindled cells. CONCLUSION We believe that the best immunohistochemical marker for confirming the diagnosis of angiomyolipoma is HMB-45, followed by melan-A. Routine use of mitf and/or tyrosinase is not indicated.

Plexiform fibromyxoma: a distinctive benign gastric antral neoplasm not to be confused with a myxoid GIST.

A great majority of gastric mesenchymal tumors are gastrointestinal stromal tumor (GIST). A rare group of non-GISTs include myxoid mesenchymal neoplasms. In this report, we describe 12 cases of a distinctive gastric tumor, named here as plexiform fibromyxoma. These tumors occurred in 5 men and 7 women of ages 7 to 75 years (median, 41 y). All tumors were located in the gastric antrum and 6 of them also extended into extragastric soft tissues or into the duodenal bulb. The tumors measured from 3 to 15 cm (median, 5.5 cm). Histologically typical was a plexiform intramural growth with multiple micronodules containing paucicellular to moderately cellular myxoid to collagenous and fibromyxoid neoplastic elements. A prominent, sometimes plexiform capillary pattern was typically present. Extramural components included subserosal nodules, and sometimes more cellular, solid nonplexiform spindle cell proliferation. The tumor cells varied from oval to spindled and had limited atypia and mitotic activity <5/50 high-power fields. Frequent ulceration, mucosal invasion, and vascular invasion (4 cases) had no adverse significance in these tumors. Immunohistochemically, the tumor cells were positive for α smooth muscle actin, and variably for CD10, and were consistently negative for KIT, DOG1, CD34, desmin, and S100 protein. No KIT or platelet-derived growth factor receptor alpha mutations were present in the 3 examined cases. None of the 4 patients who were followed from 9 to 20 years (median, 19 y) developed recurrences or metastases. Additional 3 patients survived 14 to 25 years with unknown tumor status. Review of large numbers of mesenchymal tumors in the esophagus and intestines did not reveal similar tumors. Plexiform fibromyxoma is a distinctive benign gastric antral neoplasm that should be separated from GIST, nerve sheath tumors, and other fibromyxoid neoplasms.