Report: A 58 year old man developed an AVM mimicking a vascular tumour within his left brachioradialis muscle 10 years after a nephrectomy for RCC. Ultrasound and magnetic resonance imaging did not reveal any suspicious features of the vascular lesion.The lesion was successfully removed surgically, and was later proven histopathologically to be metastatic RCC. Further imaging showed widespread metastatic disease, and the patient survived only 15 months after receiving tyrosine kinase inhibitor therapy.
Discussion: This case report aims to highlight a few important points: RCC metastases may be hypervascular, mimicking an AVM. A long disease free interval does not necessarily exclude recurrence or metastasis, as in this case, therefore long term surveillance is recommended. A high index of suspicion must be maintained to avoid delay in treatment, and biopsy of any suspicious lesion for histological examination is mandatory, albeit after many years of cancer remission. Whole body imaging with computed tomography or positron emission tomography computed tomography may detect clinically occult recurrence or metastases, and is important to guide further treatment.
METHODS: ALK gene rearrangement was detected by immunostaining of ALK protein and fluorescence in situ hybridisation (FISH) targeting at the 2p23 region.
RESULTS: The expression of ALK protein was detected in 24/34 (71%) of the cases, and it was significantly higher in childhood cases (100%) when compared to adult cases (47%). The analyses by FISH were consistent with the results from immunostaining of ALK protein, but the analyses were only successful in 15/34 (44%) cases. FISH analyses detected extra copies of ALK gene in three cases, including one case that expressed ALK protein and showed 2p23 rearrangement.
CONCLUSIONS: The current series revealed a high frequency of ALK gene rearrangement, especially in the children. Immunostaining of ALK protein is a reliable indication of ALK gene rearrangement, and is superior to FISH. However, FISH analysis is useful in detecting other genetic aberrations that are not related to ALK gene rearrangement.
RESULTS: Twenty-two patients (from 16 unrelated families) were molecularly diagnosed as XLA. Genetic testing revealed fifteen distinct mutations, including four splicing mutations, four missense mutations, three nonsense mutations, three short deletions, and one large indel mutation. These mutations scattered throughout the BTK gene and mostly affected the kinase domain. All mutations including five novel mutations were predicted to be pathogenic or deleterious by in silico prediction tools. Genetic testing confirmed that eleven mothers and seven sisters were carriers for the disease, while three mutations were de novo. Flow cytometric analysis showed that thirteen patients had minimal BTK expression (0-15%) while eight patients had reduced BTK expression (16-64%). One patient was not tested for monocyte BTK expression due to insufficient sample. Pneumonia (n=13) was the most common manifestation, while Pseudomonas aeruginosa was the most frequently isolated pathogen from the patients (n=4). Mild or asymptomatic COVID-19 was reported in four patients.
CONCLUSION: This report provides the first overview of demographic, clinical, immunological and genetic data of XLA in Malaysia. The combination of flow cytometric assessment and BTK genetic analysis provides a definitive diagnosis for XLA patients, especially with atypical clinical presentation. In addition, it may also allow carrier detection and assist in genetic counselling and prenatal diagnosis.
CASE REPORT: A 34-year-old woman with intractable epigastric pain was referred to have repeated endoscopy with biopsy. She was found to multiple gastric erosions and nodules that were diagnosed as inflammatory lesions both endoscopically and histologically. Meanwhile, she developed an acute onset of severe back pain associated with a pathologic compression fracture in the T3 thoracic vertebral body. Imaging studies disclosed a disseminated systemic disease involving abdominopelvic lymph nodes and cervical and thoracic vertebral bodies. The needle biopsy of the pelvic lymph node disclosed diffuse proliferation of monomorphic small round cells that were diffusely positive for CD30 and ALK. A diagnosis of ALK+ ALCL with a monomorphic SC pattern was rendered.
DISCUSSION: A retrospective review of the gastric biopsies with the aid of immunohistochemistry enabled us to recognise the presence of lymphomatous infiltrates with a mixed LH and SC pattern in every piece of gastric biopsies that were repeatedly misdiagnosed as inflammatory lesions. This case illustrates a significant diagnostic pitfall of the LH- and SC-patterns in ALK+ ALCL, in which the tumour cells featuring lymphoid, plasmacytoid or histiocytoid appearance can be masqueraded as inflammatory cells.