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Hb 163 159 160 167 125-175 g / L

A GP who reviews Jim ’ s case notices his increased lymphocytes .

Dr Ryan Holmes GP in Bondi Junction , Sydney , NSW .

JENNIFER , 68 , presents with a small itchy patch of scaly redness on the left lateral breast ( pictured ). It has been present for years and she has intermittently used topical steroids prescribed by various doctors . It does tend to improve with this treatment , but never completely , and it recurs when the steroid is ceased . Her medical history includes anxiety , chronic insomnia and osteoporosis for which she takes doxepin , lemborexant , periciazine and risedronate . None of these medications are new or coincide with development of the rash . She has not changed any skincare or wash products and has no dermatological history of note . Biopsy is performed which shows a moderate dermal infiltrate of lymphocytes , spongiosis and lymphocytic exocystosis into the epidermis . The lymphocytes are almost all T-cells , predominantly staining for CD3 .

MORE ON THIS DIAGNOSIS ONLINE ausdoc . com . au / spot-diagnosis with atypical CLL phenotype , and MBL with non-CLL phenotype . 3

CLL-like subtypes are most common and can be further divided into low count monoclonal B-cell lymphocytosis (< 0.5 x 10 9 / L ) which is rarely associated with progression to CLL , and high count monoclonal B cell lymphocytosis (> 0.5 x 10 9 / L ), which carries a risk of progression to CLL of 1-2 % per year . 3 Additionally , highcount MBL is associated with an increased risk of infection and development of non-haematological cancer compared with low-count MBL . 2

Preventive measures to reduce infection risk are recommended , including practising good respiratory hygiene , and regular vaccinations for influenza and COVID-19 . Patients with MBL are considered to be immunocompromised . Live vaccines are not recommended and

COVID-19 antivirals warrant consideration when indicated . 4

It is essential to counsel patients about red flag symptoms for emerging malignancy that warrant prompt medical review . These include emerging B symptoms , lymphadenopathy and clinical features of cytopenia . Educational resources may be beneficial to support this ( see online resources ).

Regular clinical and FBC monitoring is recommended , twice annually to annually , depending on subtype and progression from time of diagnosis .

Online resources Lymphoma Australia bit . ly / 3Et3CnW

References on request from kate . kelso @ adg . com . au

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What is your best ‘ zebra ’ diagnosis ?

Rachel Fieldhouse DR David Miller used to live on a yacht in the tropics and talk with other fishermen about “ things in the sea that sting and poison ”.

These conversations came flooding back to him when he encountered a rare case of ciguatera poisoning in NSW .

There are about 150 cases of ciguatera poisoning each year in Australia , according to NT Health , but it is most common in the topical and subtropical waters of the NT and northern Queensland . However , Dr Miller only saw it while working in the Northern Rivers region around 35 years ago .

“ The fish you catch in those waters do not have ciguatera ; you have to go to Cairns to catch that sort of fish ,” the retired GP told Australian Doctor .

The patient was a “ rough and ready fisherman off the trawlers ”.

“ He came in feeling unwell , with aches and pains . But he also had a curious symptom , which was circumoral paraesthesia : tingling around the mouth .

“ I remembered talking to people about this being a presenting symptom of ciguatera ,” he said .

Ciguatera poisoning is caused by the bioaccumulation of a neurotoxin produced by tiny algae , called dinoflagellates . Symptoms in humans can appear within hours or days .

“ Little fish eat dead coral and the dinoflagellates , and then bigger fish come and eat the little fish , and even bigger fish come and eat those fish , so the toxin concentrates in the muscle of the fish ,” Dr Miller said .

“ The fish itself seems quite healthy , and the toxin does not cook out either . If you eat the head or the liver , it is even worse and can be lethal .

“ If you get it twice , it can be really bad because it is a cumulative poison . “ So I asked the fisherman , ‘ Have you been eating fish lately ?’ And he told me that he had eaten some snap-frozen fish .

“ They were caught up north and had been brought down in an esky .”

With no diagnostic tests for ciguatera poisoning , Dr Miller had to rely on the patient ’ s story and symptoms .

“ The people I had spoken to about it on the boats said the only way you could really pick it was to give the fish to your cat and see if the cat got sick ,” he added . There was no treatment . “ The patient was very sick for a few weeks . I told him what I thought he had and that he needed to go home and rest ,” Dr Miller said . “ He got better . “ I told him to be very careful about eating big tropical fish after that .”

He advised GPs who suspected ciguatera to ask about their patient ’ s history of both travel and fish eating .

“ If somebody has been in the tropics — for example , maybe Fiji , Vanuatu or our own Great Barrier Reef — if they have been eating cuts of large fish and get sick , particularly if followed by tingling around the mouth , that would mean an index of suspicion .”

What is the most likely diagnosis ? a Paget ’ s disease of the breast b Chronic dermatitis c Plaque psoriasis d Mycosis fungoides

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ANSWER The answer is d . Mycosis fungoides is the most common type of cutaneous T-cell lymphoma . It is uncommon , but accounts for about 50 % of primary cutaneous lymphomas . 1 , 2

Mycosis fungoides usually occurs in mid- to late-adulthood and is more common in males and Caucasian patients . 2 It is generally an indolent disease with an estimated five-year survival of 87 %. 3 Patient age , skin stage , and presence of extracutaneous disease are the major predictors of survival . 1

Chronic itch is a common presenting feature , which may be evident before there are any other clinical signs of disease . Clinical signs , when they emerge , are usually very slowly progressive from patches to plaques , with potential eventual progression to form tumours . However , most patients are diagnosed early , prior to tumour formation . 1

Visible skin lesions usually begin as poorly defined erythematous , finely scaling patches in sun-protected areas , such as the lower trunk , breast and thighs . 1

Diagnosis can be difficult and may require multiple biopsies over time . Histopathology characteristically shows infiltrates of malignant T-lymphocytes .

Management options vary depending on patient preference and stage of disease . Options include a watch and wait approach , as individual lesions may spontaneously remit . Topical treatment options include steroids , chemotherapy and radiotherapy . Systemic therapy may involve oral retinoids , chemotherapy or immunotherapy . 1 , 2

References on request from kate . kelso @ adg . com . au