En ĉi tiu kazo la maniko estas tro longa.

Literally, it means in this case.

• en = in
• ĉi tiu = this
• kazo = case / situation

In Esperanto, kazo often means a situation or instance, not just a grammatical case or a court case.

Ĉi adds the idea of this here, making the demonstrative more specific and near to the speaker.

• tiu = that
• ĉi tiu = this
• tiu ĉi = also this

So ĉi tiu kazo and tiu ĉi kazo both mean this case.
Ĉi tiu is probably the more common order for learners to see first.

Because kazo is part of a prepositional phrase: en ĉi tiu kazo.

After a preposition like en, Esperanto normally uses the basic noun form, not the accusative:

• en la domo = in the house
• en ĉi tiu kazo = in this case

You would only use -n after en if there were a sense of movement toward something, for example:

• Mi iras en la domon = I go into the house

But here there is no motion, so kazo stays without -n.

La means the, so la maniko means the sleeve.

Esperanto uses la when the thing is specific or already understood from context. In this sentence, we are talking about a particular sleeve, not sleeves in general.

Compare:

• Maniko estas longa would sound unnatural in most contexts.
• La maniko estas longa = The sleeve is long

So la is there because this is a specific sleeve.

Maniko means sleeve, usually the sleeve of a shirt, coat, dress, and so on.

It is a noun, so it ends in -o:

• maniko = sleeve
• manikoj = sleeves

In this sentence it is singular, so the meaning is the sleeve is too long.

Because longa is a predicate adjective after estas.

In Esperanto, after esti (to be), the adjective agrees with the noun in number and case, but it does not take -n unless there is some special reason.

Here:

• la maniko = singular noun
• so the adjective is singular too: longa

That gives:

• La maniko estas longa = The sleeve is long

Not longan, because it is not a direct object.

Because -a is the normal adjective ending in Esperanto.

• longa = long
• mallonga = short

Adjectives in Esperanto usually match the noun they describe:

• la longa maniko = the long sleeve
• la manikoj estas longaj = the sleeves are long

Here longa describes maniko, so it takes the adjective ending -a.

This is a very important difference:

• tre longa = very long
• tro longa = too long

So tro means there is more than is desirable or suitable.

In this sentence, tro longa means the sleeve is longer than it should be.

This is the normal straightforward Esperanto order:

• la maniko = subject
• estas = verb
• tro longa = description

So it follows the same basic pattern as English:

• The sleeve is too long

Esperanto word order is fairly flexible, but this is the most neutral and common order.

No, not in normal Esperanto.

Ĉi tiu stays together as a demonstrative expression, and it usually comes before the noun:

• ĉi tiu kazo

You can also say:

• tiu ĉi kazo

But not kazo ĉi tiu in ordinary usage.

It can definitely mean situation, and that is exactly how it is being used here.

So:

• en ĉi tiu kazo = in this case
• also understood as in this situation

This is a very common expression in Esperanto, just as it is in English.