APCON 2010 Hyderabad
NATIONAL PATHOLOGY QUIZ – 1
Answers
Q 1: Hypopigmented mycosis fungoides
There is a small plaque surrounded by hypopigmented skin. The plaque itself shows spots of depigmentation. The biopsy reveals infiltration of the upper dermis and epidermis by uniform small cells. Distinct space is seen around the cells, particularly in the epidermis.
From the answers, it would seem that these cells have been considered variously as lymphoid cells, nevus cells or mast cells.
Most of those who thought they were Nevus cells made a diagnosis of ‘Halo nevus’ because of the hypopigmentation. But, halo nevi are characterized by a heavy lymphoid infiltrate. Also, nevus cells in the dermis tend to be in groups rather lying singly. Further, nevus cells in the epidermis would be at the epidermo-dermal junction – the junctional component. They would not be expected higher up as in this case; unless it is a regressing melanoma which can also have a halo effect. But a heavy lymphoid infiltrate would again be expected.
Mast cells in urticaria pigmentosa can have a resemblance to the cells in the picture. But the hypopigmentation and the striking epidermotropism are points against.
So we are left with lymphoid cells. Are they lymphoma cells of mycosis fungoides (including variants like Woringer-Kollop disease) or lymphocytes of early vitiligo? The cells do not seem to be ordinary small lymphocytes from the size and the pericellular spaces.
Mycosis fungoides in a child this young? Yes. This can occur, especially the hypopigmented form. This type occurs more commonly in the dark skinned and is often of the CD8 phenotype. The lesional CD8 cells are believed to affect the function of melanocytes leading to hypopigmentation, akin to vitiligo.
See a nice Pautrier microabscess (arrows) and confirmation that the cells are lymphoid (CD3 staining).
Correct answers: 18.9%
Links
1. Hypopigmented mycosis fungoides – pubmed abstracts
2. Pathogenesis of hypopigmented MF
3. Hypopigmented MF vs Vitiligo
Q 2: Endocrine microadenomatosis of the pancreas
Multiple microscopic nodules within the pancreas. The cells in the nodules are arranged in the form of ribbons and glands. They are sharply stained by the antibody in the IHC picture. The antibody is not cytokeratin since the exocrine pancreatic tissue is not stained; this effectively rules out an adenocarcinoma of ductal or exocrine origin. In this case, the antibody used was chromogranin.
The majority diagnosed this as nesidioblastosis / islet cell hyperplasia. If it were so, the aggregates would be solid as in the normal islets of Langerhans. The ribbon pattern suggests an endocrine tumor, albeit of microscopic dimensions.
Multiple microadenomas are most common in MEN1 and von Hippel Lindau syndrome. It is rare outside of these syndromes.
Glucagon Cell Adenomatosis is a recently described entity which appears to be non familial and in which all the adenomas exclusively express glucagon.
The current patient was diabetic but had no skin lesions. The sections are yet to be stained for glucagon.
Correct answers: 5.2%
Links
1. Pancreatic endocrine microadenomatosis: Pubmed abstracts
Q 3: BK virus-associated nephropathy
Tubular structures lined by low cuboidal cells. One cannot help notice the large cells that literally stick out. The nuclei are homogenous or ‘ground glass’ and not owl eyed as in the case of cytomegalovirus inclusions.
There are a few tiny specks of artefactual dust like material in the section. A few of you have interpreted these as organisms or leukocytoclasia. But as my erstwhile professor was fond of saying; ‘when Elizabeth Taylor is on the screen, why bother with the bit players?’.
Correct answers: 31.6%
Links
1. BK virus associated nephropathy
Q 4: Choriocarcinoma of the ovary
This girl presented with amenorrhea and abdominal mass. Her entire left ovary was replaced by the hemorrhagic mass shown in the picture. The squash cytology from the mass shows clusters of cells with light staining cytoplasm as well as multinucleated giant cells. The combination of these findings (hemorrhagic mass and two types of cells) makes choriocarcinoma a strong possibility. Here is the histology.
This was a primary ovarian tumor. No other elements were seen.
Correct answers: 34.9%
Links
1. Cytology of choriocarcinoma: pubmed abstracts
2. A recent full text case report
Q 5: Tuberculous epididymitis
In this paratesticular mass, the prime question would be; is it tumor or inflammation? The fact that the shape of the epididymis is retained would argue in favor of the latter. A tumor would be expected to be expansile with either round or oval shape or frankly infiltrative. Here the whole lesion appears to be confined within the epididymis. The areas of necrosis and the grey white tumor like areas point to tuberculosis.
Correct answers: 54.7%
Links:
Q 6: Touidine blue stain in accelerated phase of CML
A peripheral smear with high white cell count. See the lightly stained cells in the background. The whole range of myeloid differentiation is seen. The bright pink cells in this context must be basophils, stained by a metachomatic stain like Toluidine blue. A basophil count of about 30% would suggest diagnosis of accelerated phase of chronic myeloid leukemia.
Nothing like educated guesses!
Correct answers: 26.4%
Links:
1. Basophils in accelerated phase of CML
Q 7: Frequency of CCR5Δ32 mutation and HIV susceptibility in Indian population
A 32 bp deletion (CCR5Δ32, rs333) in the CCR5 gene has been found to protect individuals against HIV infection. The frequency of CCR5Δ32 was extremely low in the Indian population. The pooled allele frequency of the CCR5Δ32 mutation in India is shown in the map. There is a high-to-low gradient from north to south with the maximum of about 6% in a north Indian population. This correlates with antenatal clinical HIV prevalence surveys that report high frequency of HIV in south Indian populations as compared to the North.
However, even the frequency of 6% in the North-west is much lower when compared to the Caucasian population of Europe (16%).
Correct answers: 70.3%
Links:
1. Indian Genome Variation Consortium study
Q 8: Renal cortical necrosis in hemolytic uremic syndrome
The glomeruli and tubules are necrotic. The tubular lining cells are mostly devoid of nuclei and the glomeruli are almost structureless hemorrhagic masses. There are many causes for cortical necrosis. The clue here are the bright pink fibrin thrombi in the small vessels (arrows). In a child, this would strongly point to hemolytic uremic syndrome (HUS) as the likely cause.
Correct answers: 40.1%
Links:
1. Hemolytic uremic syndrome – renal pathology